Methods and systems for supplying hydrogen to a hydrocatalytic reaction

ABSTRACT

A bottom fraction of a product of a hydrocatalytic reaction is gasified to generate hydrogen for use in further hydrocatalytic reactions. In one embodiment, an overhead fraction of the hydrocatalytic reaction is further processed to generate higher molecular weight compounds. In another embodiment, a product of the further processing is separated into a bottom fraction and an overhead fraction, where the bottom fraction is also gasified to generate hydrogen for use in further hydrocatalytic reactions.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/879,422, filed on Sep. 18, 2013 and U.S. Provisional Application No.61/919,033, filed on Dec. 20, 2013, the disclosures of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to ahydrocatalytic reaction and more specifically, to systems and methodssupplying hydrogen to the hydrocatalytic reaction through gasificationof a fraction of a product stream of the hydrocatalytic reaction.

BACKGROUND

This section is intended to introduce various aspects of the art, whichmay be associated with exemplary embodiments of the present invention.This discussion is believed to assist in providing a framework tofacilitate a better understanding of particular aspects of the presentinvention. Accordingly, it should be understood that this section shouldbe read in this light, and not necessarily as admissions of any priorart.

A number of substances of commercial significance may be produced fromnatural sources, including biomass. Cellulosic biomass may beparticularly advantageous in this regard due to the versatility of theabundant carbohydrates found therein in various forms. As used herein,the term “cellulosic biomass” refers to a living or formerly livingbiological material that contains cellulose. The lignocellulosicmaterial found in the cell walls of higher plants is the world's largestsource of carbohydrates. Materials commonly produced from cellulosicbiomass may include, for example, paper and pulpwood via partialdigestion, biofuels, including bioethanol by fermentation.

Development of fossil fuel alternatives derived from renewable resourceshave received recent attention. Cellulosic biomass has garneredparticular attention in this regard due to its abundance and theversatility of the various constituents found therein, particularlycellulose and other carbohydrates. Despite promise and intense interest,the development and implementation of bio-based fuel technology has beenslow. Existing technologies have heretofore produced fuels having a lowenergy density (e.g., bioethanol) and/or that are not fully compatiblewith existing engine designs and transportation infrastructure (e.g.,methanol, biodiesel, Fischer-Tropsch diesel, hydrogen, and methane).Moreover, conventional bio-based processes have typically producedintermediates in dilute aqueous solutions (>50% water by weight) thatare difficult to further process. Energy- and cost-efficient processesfor processing cellulosic biomass into fuel blends having similarcompositions to fossil fuels would be highly desirable to address theforegoing issues and others.

When converting cellulosic biomass into fuel blends and other materials,cellulose and other complex carbohydrates therein can be extracted andtransformed into simpler organic molecules, which can be furtherprocessed thereafter. Subsequent transforming reactions include varioushydrocatalytic reactions, such as hydrogenation and/or hydrogenolysisreactions, which require hydrogen. While external hydrogen can beprovided, such a hydrogen source may not help reduce the carbonfootprint of any eventual fuel product, such as when it is based onnatural gas reforming.

Further, in addition to the desired carbohydrates, other substances maybe present within cellulosic biomass that can be especially problematicto deal with in an energy- and cost-efficient manner. For example,during cellulosic biomass processing, the significant quantities oflignin present in cellulosic biomass may lead to fouling of processingequipment, potentially leading to costly system down time. Thesignificant lignin quantities can also lead to realization of arelatively low conversion of the cellulosic biomass into useablesubstances per unit weight of feedstock.

As evidenced by the foregoing, the efficient conversion of cellulosicbiomass into fuel blends and other materials is a complex problem thatpresents immense engineering challenges. The present disclosureaddresses these challenges and provides related advantages as well.

SUMMARY

The present disclosure describes systems and methods supplying hydrogento a hydrocatalytic biomass conversion reaction throughgasification—also known as partial combustion—of a fraction of a productstream of the hydrocatalytic reaction. In a preferred embodiment, thefraction comprises lignin, lignin-derived compounds, and/or unextractedamounts of cellulose and hemi-cellulose. In another embodiment, theproduct stream fraction subject to gasification can further comprises aC₁₄ or greater hydrocarbon, such as an olefin, a paraffin, an aromatic,a cycloalkane, caramels, and/or other oxygenate condensation products.The fraction of the product stream to be gasified can be provided to thegasification zone as one or more input streams. For example, in oneembodiment, the gasification zone can have one input comprising lignin,lignin-derived compounds, and/or unextracted amounts of cellulose andhemi-cellulose and another input comprising C₁₄ or greater hydrocarbons.In another embodiment, the gasification zone has one input streamcomprising lignin, lignin-derived compounds, and/or unextracted amountsof cellulose and hemi-cellulose, as well as an olefin, a paraffin, anaromatic, a cycloalkane, and/or other hydrocarbons with a carbon numberof C₁₄ or greater, including caramels and other oxygenate condensationproducts.

According to one aspect of the invention, there is provided a methodcomprising: (a) providing a biomass feedstock containing cellulose andwater; (b) contacting the biomass feedstock with hydrogen in thepresence of a catalyst capable of activating molecular hydrogen to forma hydrocatalytically treated mixture. The method further comprises (c)separating the hydrocatalytically treated mixture into at least a firstbottom fraction and a first overhead fraction, wherein the first bottomfraction comprises at least one compound having a separation pointhaving a temperature in a range of about 100 to 600 degrees C. and apressure of about atmospheric pressure; (d) partially oxidizing at leasta portion of the first bottom fraction to produce a gas mixturecomprising carbon monoxide and hydrogen. The method additionallycomprises (e) subjecting at least a portion of the gas mixture to awater gas shift reaction to generate hydrogen and carbon dioxide; and(f) providing at least a portion of the hydrogen from step (e) for usein step (b).

In one embodiment, the first bottom fraction comprises at least onecompound having a separation point having a temperature in a range ofabout 100 to 500 degrees C. and a pressure in a range of about 1 to 100Torr, preferably about 3 to 20 Torr, such as about 10 Torr. In anotherembodiment, the first bottom fraction comprises at least one compoundhaving a separation point with a temperature in a range of about 200 to450 degrees C. and a pressure in a range of about 1 to 100 Torr,preferably about 3 to 20 Torr, such as about 10 Torr.

In one embodiment, the hydrocatalytically treated mixture comprises aplurality of hydrocarbon, including oxygenated hydrocarbon molecules,the method further comprising processing at least a portion of theplurality of hydrocarbons, including oxygenated hydrocarbon molecules,to form a fuel blend comprising a higher hydrocarbon. In anotherembodiment, the portion of the first bottom fraction subject to partialoxidation comprises lignin, lignin-derived compounds, and/or unextractedamounts of cellulose and hemi-cellulose. In another embodiment, at leasta portion of the first overhead fraction is subject to a furtherprocessing reaction to produce a product stream comprising a highermolecular compound.

In yet another embodiment, the method further comprises separating atleast a portion of the product stream comprising a higher molecularcompound into a second overhead fraction and a second bottom fraction,wherein the second bottom fraction comprises at least one compoundhaving a separation point having a temperature in a range of about 100to 500 degrees C. and a pressure in a range of about 0.10 to 7 bar, andpartially oxidizing at least a portion of the second bottom fraction toproduce a gas mixture comprising carbon monoxide and hydrogen. Themethod further comprises subjecting at least a portion of the gasmixture generated from partial oxidation of at least a portion of thesecond bottom fraction to a water gas shift reaction to generatehydrogen and carbon dioxide; and providing at least a portion of thehydrogen from the second bottom fraction to step (b).

In one embodiment, the second bottom fraction comprises at least onecompound having a separation point having a temperature in a range ofabout 150 to 400 degrees C. and a pressure in a range of about 0.10 to 7bar. In another embodiment, the second bottom fraction comprises atleast one compound having a separation point having a temperature in arange of about 200 to 400 degrees C. and a pressure in a range of about0.10 to 7 bar.

In one embodiment, the partially oxidizing step of at least a portion ofthe first bottom fraction comprises using a gasifier. In anotherembodiment, the partially oxidizing step of at least a portion of thesecond bottom fraction comprises using a gasifier. In one embodiment,the gasifier is selected from the group consisting of a moving-bedgasifier, a fluid-bed gasifier, an entrained-flow gasifier, and anycombination thereof. In yet another embodiment, the method furthercomprises routing at least a portion of the first or second bottomfraction to the gasifier, wherein the portion can be a solid, liquid, ora combination thereof. In one embodiment, the gasifier comprises anentrained-flow gasifier and the portion of the first or second bottomfraction is routed as a liquid. In yet another embodiment, the samegasifier is used for the partially oxidizing step of at least a portionof the first bottom fraction and the partially oxidizing step of atleast a portion of the second bottom fraction.

In one embodiment, the portion of the first bottom fraction subject topartial oxidation has a viscosity of about 1 to 10,000 centipoises (cP)at a temperature of about 75 degrees C. In another embodiment, theportion of the first bottom fraction subject to partial oxidation has aviscosity of about 100 to 5,000 centipoises (cP) at a temperature ofabout 75 degrees C. In another embodiment, the portion of the firstbottom fraction subject to partial oxidation has a viscosity of about500 to 1,000 centipoises (cP) at a temperature of about 75 degrees C. Inanother embodiment, the first bottom fraction subject to partialoxidation has a kinematic viscosity of about 320 centistokes or less (orabout 320 centipoises depending on specific gravity) at about thetemperature at which the bottom fraction is produced, in one embodiment,it is above about 200 degrees C.

Other advantages and features of embodiments of the present inventionwill become apparent from the following detailed description. It shouldbe understood, however, that the detailed description and the specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of thepresent disclosure, and should not be viewed as exclusive embodiments.The subject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, as willoccur to one having ordinary skill in the art and the benefit of thisdisclosure.

FIG. 1 shows an illustrative schematic of one embodiment to supplyhydrogen to a hydrocatalytic reaction through gasification of a fractionof a product stream of the hydrocatalytic reaction according to aspectsof the invention.

FIG. 2 shows an illustrative schematic of another embodiment to supplyhydrogen to a hydrocatalytic reaction through gasification of a fractionof a product stream of the hydrocatalytic reaction according to aspectsof the invention.

FIG. 3 shows an illustrative schematic of an exemplary moving bedgasifier that can be used in one embodiment according to aspects of theinvention.

FIG. 4 shows an illustrative schematic of an exemplary stationaryfluid-bed gasifier that can be used in one embodiment according toaspects of the invention.

FIG. 5 shows an illustrative schematic of an exemplary circulatingfluid-bed gasifier that can be used in one embodiment according toaspects of the invention.

FIG. 6 shows an illustrative schematic of an exemplary transportfluid-bed gasifier that can be used in one embodiment according toaspects of the invention.

FIG. 7 shows an illustrative schematic of an exemplary entrained-flowgasifier with a membrane wall and diametrically opposed burners that canbe used in one embodiment according to aspects of the invention.

FIG. 8 shows an illustrative schematic of an exemplary entrained-flowgasifier with a refractory lined wall and a top burner that can be usedin one embodiment according to aspects of the invention.

FIG. 9A shows an illustrative schematic of an exemplary entrained-flowgasifier with a membrane wall and a top burner that can be used in oneembodiment according to aspects of the invention.

FIG. 9B is a cross-sectional view taken along the line A-A′ of FIG. 9A.

FIG. 10 is shows an illustrative schematic of an exemplary coolingsystem that can be used in one embodiment according to aspects of theinvention.

DETAILED DESCRIPTION

Embodiments of the present invention relate to systems and methodssupplying hydrogen to the hydrocatalytic reaction through gasificationof a fraction of the product stream of the hydrocatalytic reaction,preferably a bottom fraction. In a preferred embodiment, the bottomfraction comprises lignin, lignin-derived compounds, and/or unextractedamounts of cellulose and hemi-cellulose. Non-limiting exemplarylignin-derived compounds can include partially depolymerized ligninmoieties containing 5-′5, phenylcoumaran, and β-O-4 linkages ascharacterized by monomeric compounds, phenol, o-cresol, p-cresol,anisole, 4-methylanisole, catechol, guaiacol, 4-methylguaiacol,1,3-dimethoxybenzene, syringol, and vanillin. Other derived compoundsinclude methanol, methoxyphenol, methyl phenol, dimethyl phenol, ethylphenol, methyl ethyl phenol, methoxypropylphenol, benzene diol, propylphenol, and similar compounds. The bottom fraction being gasified canfurther comprise oligomeric derivatives of carbohydrates, andintermediates, including phenolic intermediates derived from lignin,unreacted or partially hydrolyzed cellulose and hemicellulose, cellulosecondensation products, caramelans, and cross polymerization products ofsugars and phenolic intermediates. In another embodiment, a secondbottom fraction is subject to gasification, where the second bottomfraction comprises a C₁₄ or greater hydrocarbon, including an olefin, aparaffin, an aromatic, or a cycloalkane. A particular hydrocatalyticreaction comprises contacting a biomass feedstock with hydrogen in thepresence of a metal catalyst capable of activating molecular hydrogen toform a hydrocatalytically treated mixture. In certain embodiments, thehydrocatalytically treated mixture comprises a plurality of hydrocarbon,including oxygenated hydrocarbon molecules, which can be suitable foruse in transportation fuels and industrial chemicals. As mentioned, in apreferred embodiment, the fraction of the hydrocatalytically treatedmixture that is subject to gasification comprises at least one of heavyend components, including caramelans, lignin and lignin-derivedcompounds, and cross polymerization products of sugars and lignincomponents. In one embodiment, the bottom fraction of thehydrocatalytically treated mixture has a separation point having atemperature in a range of about 100 to 600 degrees C. and a pressureabout atmospheric pressure, more preferably a temperature in a range ofabout 100 to 500 degrees C. and a pressure in a range of about 1 to 100Torr, preferably about 3 to 20 Torr; most preferably a temperature in arange of about 200 to 450 degrees C. and a pressure of about 1 to 100Torr, preferably about 3 to 20 Torr. As used herein, a “separationpoint” refers to a temperature and pressure at or above which acomponent does not become a vapor or gas. For example, components in abottom fraction of the hydrocatalytically treated mixture having aseparation point having a temperature in a range of about 100 to 600degrees C. and a pressure of about atmospheric pressure means thosecomponents do not become a vapor or gas, e.g., vaporize, at or aboveabout 100 to 600 degrees C. and a pressure of about atmosphericpressure. In another preferred embodiment, the portion being gasifiedfurther comprises a second bottom portion comprising C₁₄ or greaterhydrocarbons having a separation point having a temperature in a rangeof about 100 to 500 degrees C., more preferably a temperature in a rangeof about 150 to 400 degrees C., and most preferably in a range of about200 to 400 degrees C., and a pressure in a range of about 0.10 to 7 bar.It is understood that components or compounds in a bottom fraction ofthe hydrocatalytically treated mixture may degrade or convert intodifferent compounds at a separation point. An advantage of embodimentsof the invention may include reducing the carbon footprint of the fuelsformed from the thermocatalytic reaction because at least a portion ofthe hydrogen used in the thermocatalytic reaction has low carbonfootprint. A fuel with low carbon footprint can qualify for certaingovernmental status that provides certain benefits. While particularembodiments provide certain advantages or benefits, they are notrequired as part of the invention.

As used herein, the term “hydrocarbons” refers to compounds containingboth carbon and hydrogen without reference to other elements that may bepresent. Thus, heteroatom-substituted compounds are also describedherein by the term “hydrocarbons.” The term “hydrocatalytic treatment”refers to a type of thermocatalytic reaction where the reaction is withhydrogen in the presence of a catalyst capable of activating molecularhydrogen, preferably a metal catalyst.

Various exemplary embodiments of the invention are further describedwith reference to the drawings. When like elements are used in one ormore figures, identical reference characters will be used in eachfigure, and a detailed description of the element will be provided onlyat its first occurrence. Some features of the embodiments may be omittedin certain depicted configurations in the interest of clarity. Moreover,certain features such as, but not limited to, pumps, valves, gas bleeds,gas inlets, fluid inlets, fluid outlets and the like have notnecessarily been depicted in the figures, but their presence andfunction will be understood by one having ordinary skill in the art.

Referring to FIG. 1, biomass feedstock 11 is provided to hydrocatalytictreatment system 12 where biomass feedstock 11 is reacted with hydrogenin the presence of a metal catalyst capable of activating molecularhydrogen to produce hydrocatalytically treated mixture 13.Hydrocatalytic treatment system 12 is coupled to separation zone 14 toprovide hydrocatalytically treated mixture 13 to separation zone 14. Ina preferred embodiment, hydrocatalytic treatment system 12 is in fluidcommunication with separation zone 14. As shown, at least a portion ofhydrocatalytically treated mixture 13 is separated or fractionated intoat least two fractions in separation zone 14: overhead fraction 15 andbottom fraction 16. In a preferred embodiment, overhead fraction 15comprises compounds having a vaporization point that is lower than thatof bottom fraction 16, and bottom fraction 16 comprises compounds havinga separation point having a temperature in a range of about 100 to 600degrees C. and pressure of about atmospheric pressure, more preferably atemperature in a range of about 100 to 500 degrees C. and a pressure ina range of about 1 to 100 Torr, preferably about 3 to 20 Torr; mostpreferably a temperature in a range of about 200 to 450 degrees C. and apressure in a range of about 1 to 100 Torr, preferably about 3 to 20Torr. That is, overhead fraction 15 comprises compounds that wouldvaporize at a temperature in a range about 100 to 600 degrees C. andpressure of about atmospheric pressure, more preferably a temperature ina range of about 100 to 500 degrees C. and about 1 to 100 Torr,preferably about 3 to 20 Torr; most preferably a temperature in a rangeof about 200 to 450 degrees C. and about 1 to 100 Torr, preferably about3 to 20 Torr. Compounds in overhead fraction 15 can be referred to aslight components while compounds in bottom fraction 16 can be referredto as heavy components.

Referring to FIG. 1, at least a portion of bottom fraction 16 isprovided to gasification system 17 for partial oxidation.

In one embodiment, oxidant stream 18 provides gasification system 17with an oxidant suitable to gasify a carbonaceous material. As usedherein, the term “oxidant” includes any oxygen containing compoundcapable of contributing to the gasification of at least a portion of acarbonaceous material, such as bottom fraction 16. Illustrative oxidantscan include, but are not limited to, air, oxygen, essentially oxygen,oxygen-enriched air, mixtures of oxygen and air, mixtures of air and/oroxygen with steam, mixtures of oxygen and one or more inert gases, forexample, nitrogen and/or argon, or any combination thereof. Oxidantstream 18 can contain about 20 vol % oxygen or more, about 30 vol %oxygen or more, about 40 vol % oxygen or more, about 50 vol % oxygen ormore, about 60 vol % oxygen or more, about 65 vol % oxygen or more,about 70 vol % oxygen or more, about 75 vol % oxygen or more, about 80vol % oxygen or more, about 85 vol % oxygen or more, about 90 vol %oxygen or more, about 95 vol % oxygen or more, or about 99 vol % oxygenor more. As used herein, the term “essentially oxygen” refers to anoxygen stream containing more than 50 vol % oxygen. As used herein, theterm “oxygen-enriched air” refers to a gas mixture containing oxygen ina range of about 21 to 50 vol % oxygen. In one embodiment, oxygenenriched air or essentially oxygen can be supplied by one or more airseparation units (“ASU”) or a pressure swing absorber. The ASU canprovide a nitrogen-lean and oxygen-rich stream for oxidant stream 18,thereby minimizing the nitrogen concentration in the system. The ASU canbe a high-pressure, cryogenic type separator that can be supplementedwith air. In one embodiment, up to about 50 vol %, or up to about 40 vol%, or up to about 30 vol %, or up to about 20 vol %, or up to about 10vol % of the total oxidant fed to the gasifier can be supplied by theASU. In a preferred embodiment, a moderator gas (not shown) can besupplied to gasification system 17, separately or with oxidant stream18, to control the temperature of gasification system 17. Non-limitingexamples of suitable moderator gases include steam, carbon dioxide, or acombination thereof. Conditions for applying oxidant stream 18 and themoderator gas, if used, are known to those skilled in the art.

In another embodiment, oxidant stream 18 can also include steam and/ornatural gas, which can be delivered to gasification system 17 separatelyor with the oxidant in stream 18. The partial oxidation of bottomfraction 16 produces gas mixture 19 comprising hydrogen and carbonmonoxide. Gas mixture 19 can be referred to as synthesis gas or syngas.As shown, gasification system 17 is coupled to water-gas shift reactionzone, WGS zone 20, to provide gas mixture 19 to WGS zone 20. As can beseen, WGS zone 20 is external to hydrocatalytic treatment system 12. Inone embodiment, gasification system 17 is preferably in fluidcommunication with WGS zone 20. At least a portion of gas mixture 19 issubject to a water gas shift reaction in WGS zone 20, which converts thecarbon monoxide from gas mixture 19 to hydrogen rich shifted synthesisgas product comprising hydrogen and carbon dioxide, which is shown asstream 21. WGS zone 20 is coupled to hydrocatalytic treatment system 12to provide stream 21 to hydrocatalytic treatment system 12. In oneembodiment, WGS zone 20 is preferably in fluid communication withhydrocatalytic treatment system 12. As shown, at least a portion of thehydrogen rich synthesis gas product generated in WGS zone 20 is routedto hydrocatalytic treatment system 12 via stream 21 for use in ahydrocatalytic reaction.

In a preferred embodiment, the hydrogen contained in stream 21 isprovided to hydrocatalytic treatment system 12 at a pressure in a rangeof about 10-200 bar, more preferably about 20 to 100 bar, mostpreferably 30 to 80 bar, and a temperature in a range of 35-450 degreesC., more preferably about 50 to 250 degrees C., and most preferablyabout 100 to 200 degrees C. In some embodiments, steam generated ingasification system 17 can be routed to other processes for use in anysuitable manner known to those skilled in the art, such as a heatingmedium. For example, in one embodiment, gasification system 17 iscoupled to hydrocatalytic treatment system 12 to provide hydrocatalytictreatment system 12 with steam generated in gasification system 17 viastream 27 as shown in FIGS. 1 and 2. In a preferred embodiment, thesteam contained in stream 27 is provided to hydrocatalytic treatmentsystem 12 at a pressure in a range of about 20-120 bar, more preferablyabout 40 to 100 bar, most preferably 40 to 90 bar. The steam can besaturated or with superheat. In one embodiment, steam from anothersource can be provided to hydrocatalytic treatment system 12. In such anembodiment, stream 27 can be combined with steam from the boiler and themixture of both can be provided as one stream or steam from the boilerand steam from gasification system 17 can be provided separately. Inaddition or alternatively, steam from gasification system 17 can berouted to WGS zone 20 via stream 27 as shown in FIGS. 1 and 2 tofacilitate additional hydrogen generation.

FIG. 2 comprises similar processes and systems and FIG. 1, and furtherincludes separation zone 14 coupled to processing zone 22 to provideprocessing zone 22 with overhead fraction 15. In one embodiment,separation zone 14 is preferably in fluid communication with processingzone 22. In another embodiment, at least a portion of overhead fraction15 is subject to one or more reactions in processing zone 22 to produceproduct stream 23 comprising higher molecular weight compounds.Processing zone 22 is coupled to separation zone 24. In one embodiment,processing zone 22 is preferably in fluid communication with separationzone 24. In another embodiment, product stream 23 is further separatedor fractionated into at least two fractions in separation zone 24:overhead fraction 25 and bottom fraction 26. In a preferred embodiment,a first fraction exiting separation zone 24 is overhead fraction 25comprising compounds having a vaporization point that is below thevaporization point of bottom fraction 26. A second fraction exitingseparation zone 24 is preferably bottom fraction 26 comprising compoundshaving a separation point having a temperature in a range of about 100to 500 degrees C., more preferably a temperature in a range of about 150to 400 degrees C., and most preferably in a range of about 200 to 400degrees C., and a pressure in a range of about 0.10 to 7 bar. That is,overhead fraction 25 comprises compounds that would vaporize at atemperature in a range about 100 to 500 degrees C., more preferably atemperature in a range of about 150 to 400 degrees C., and mostpreferably in a range of about 200 to 400 degrees C., and a pressure ina range of about 0.10 to 7 bar. In one embodiment, bottom fraction 26comprises a C₁₄ or greater hydrocarbon, such as an olefin, a paraffin,an aromatic, a cycloalkane, caramels, and/or other oxygenatecondensation products. Separation zone 24 is coupled to gasificationsystem 17. In one embodiment, separation zone 24 is preferably in fluidcommunication with gasification system 17. In addition to oralternatively to bottom fraction 16, in one embodiment, at least afraction of bottom fraction 26 is provided to gasification system 17also for partial oxidation, generating syngas in gas mixture 19 that canbe converted to hydrogen in WGS zone 20 for further use in ahydrocatalytic reaction in hydrocatalytic treatment system 12.

Referring to FIGS. 1-2, in practice of one embodiment, biomass feedstock11 is introduced to hydrocatalytic treatment system 12 along with apredetermined amount of hydrogen or hydrogen containing gas, preferablyfrom stream 21. Additional hydrogen from an external source can also beprovided to hydrocatalytic treatment system 12 as needed, for example,during start up when gasification system 17 may not yet generate asufficient amount of hydrogen. In such circumstance, in one embodiment,natural gas can also be provided to gasification system 17. Biomassfeedstock 11 reacts with hydrogen in the presence of a metal catalystcapable of activating molecular hydrogen to form hydrocatalyticallytreated mixture 13, at least a portion of which is discharged and passedto separation zone 14 where mixture 13 is separated into overheadfraction 15 and bottom fraction 16 comprising lignin and lignin-derivedcompounds. Bottom fraction 16 is discharged and provided to gasificationsystem 17 where it is partially oxidized with oxidant provided by stream18 to generate gas mixture 19 comprising hydrogen and carbon monoxide,or synthesis gas. Gas mixture 19 is discharged and introduced to WGSzone 20 to generate stream 21 comprising a hydrogen rich shiftedsynthesis gas product. Stream 21 is discharged and routed tohydrocatalytic treatment system 12 for use in a hydrocatalytic reaction.In an alternative embodiment (not shown), a portion of overhead fraction15 can also be routed to gasification system 17.

Referring to FIG. 2, in one embodiment, at least a portion of overheadfraction 15 is discharged and passed to processing zone 22 to produceproduct stream 23 comprising higher molecular weight compounds. Productstream 23 is discharged and passed to separation zone 24 to separateproduct stream 23 into overhead fraction 25 and bottom fraction 26,which can be discharged and routed to gasification system 17 for partialoxidation to additionally generate gas mixture 19.

Any suitable type of biomass can be used as biomass feedstock 11.Suitable cellulosic biomass sources may include, for example, forestryresidues, agricultural residues, herbaceous material, municipal solidwastes, waste and recycled paper, pulp and paper mill residues, and anycombination thereof. Thus, in some embodiments, a suitable cellulosicbiomass may include, for example, corn stover, straw, bagasse,miscanthus, sorghum residue, switch grass, bamboo, water hyacinth,hardwood, hardwood chips, hardwood pulp, softwood, softwood chips,softwood pulp, duckweed, and any combination thereof. Leaves, roots,seeds, stalks, husks, and the like may be used as a source of thecellulosic biomass. Common sources of cellulosic biomass may include,for example, agricultural wastes (e.g., corn stalks, straw, seed hulls,sugarcane leavings, nut shells, and the like), wood materials (e.g.,wood or bark, sawdust, timber slash, mill scrap, and the like),municipal waste (e.g., waste paper, yard clippings or debris, and thelike), and energy crops (e.g., poplars, willows, switch grass, alfalfa,prairie bluestream, corn, soybeans, and the like). The cellulosicbiomass may be chosen based upon considerations such as, for example,cellulose and/or hemicellulose content, lignin content, growingtime/season, growing location/transportation cost, growing costs,harvesting costs, and the like.

Biomass feedstock 11 may be natively present in any sizes, shapes, orforms, or it may be further processed prior to entering hydrocatalytictreatment in system 12. Examples of further processing include washing(such as, with water, an acid, a base, combinations thereof, and thelike), torrefaction, liquefaction, such as pyrolysis, or reduction insize. In some embodiments, the reduction in size may include chopping,grounding, shredding, pulverizing, and the like to produce a desiredsize. Thus, in some embodiments, providing a biomass material cancomprise harvesting a lignocelluloses-containing plant such as, forexample, a hardwood or softwood tree. The tree can be subjected todebarking, chopping to wood chips of desirable thickness, and washing toremove any residual soil, dirt and the like.

Biomass feedstock 11 is preferably treated to convert the cellulose andother complex carbohydrates into a more usable form, which can befurther transformed into compounds with one or more alcohol functionalgroups through downstream reactions. While suitable for furthertransformation, soluble carbohydrates can be very reactive and canrapidly degrade to produce caramelans and other degradation products,especially under higher temperature conditions, such as above about 150°C. One way to protect soluble carbohydrates from thermal degradation isto subject them to one or more catalytic reduction reactions, which mayinclude hydrogenation and/or hydrogenolysis reactions. Depending on thereaction conditions and catalyst used, reaction products formed as aresult of conducting one or more catalytic reduction reactions onsoluble carbohydrates may comprise, as mentioned, one or more alcoholfunctional groups, particularly including triols, diols, monohydricalcohols, and any combination thereof, some of which may also include aresidual carbonyl functionality (e.g., an aldehyde or a ketone). Suchreaction products are typically more thermally stable than solublecarbohydrates and may be readily transformable into fuel blends andother materials through conducting one or more downstream furtherprocessing reactions. That is, soluble carbohydrates formed duringhydrothermal digestion may be intercepted and converted into more stablecompounds before they have an opportunity to significantly degrade, evenunder thermal conditions that otherwise promote their degradation.

In a preferred embodiment, a hydrocatalytic reaction that takes place insystem 12 of FIGS. 1 and 2 is conducted in the presence of hydrogen,specifically molecular hydrogen, with a catalyst that is capable ofactivating molecular hydrogen to participate in various reactions suchas hydrothermal digestion; catalytic reduction reactions, includinghydrogenation, hydrogenolysis, and/or hydrodeoxygenation; and optionallyhydrodesulfurization and hydrodenitrification. Any suitablehydrocatalytic reaction can take place in system 12. Exemplaryhydrocatalytic reactions, including hydrogenation and hydrogenolysis,are described in U.S. Publication Application No. US2011/0154721, thedisclosure of which is incorporated herein by reference in its entirety.

For example, in one embodiment, hydrocatalytic treatment system 12 cancomprise a reaction as described in US2011/0154721, such as ahydrogenolysis reaction and/or a hydrogenation reaction, where solublecarbohydrate is catalytically reacted with hydrogen to produce desiredreaction products. Examples of desired or suitable reactions productsmay include, but are not limited to, alcohols, polyols, aldehydes,ketones, other oxygenated intermediates, and any combination thereof.For instance, hydrocatalytic treatment system 12 can comprisehydrogenation reaction 104 and/or hydrogenolysis reaction 106 of FIGS.1-3 of US2011/0154721. The descriptions corresponding to hydrogenationreaction 104 and hydrogenolysis reaction 106 are provided byUS2011/0154721, which is incorporated by reference in its entirety, andthus need not be repeated.

In such an embodiment, at least a portion of the products exitinghydrogenation reaction 104 and/or hydrogenolysis reaction 106 FIGS. 1-3of US2011/0154721 can be routed to separation zone 14 shown in FIGS.1-2, so a bottom fraction 16 can be separated from the products streamas described herein. For instance, in one embodiment, separation zone 14can comprise separation unit 108 in FIG. 3 of US2011/0154721, which canprovide a fraction having a separation point having a temperature in arange of about 100 to 600 degrees C. and a pressure of about atmosphericpressure, more preferably a temperature in a range of about 100 to 500degrees C. and a pressure in a range of about 1 to 100 Torr, preferablyabout 3 to 20 Torr; most preferably a temperature in a range of about200 to 450 degrees C. and a pressure in a range of about 1 to 100 Torr,preferably about 3 to 20 Torr. The fraction can be routed togasification system 17 of FIGS. 1-2 for partial oxidation to generategas mixture 19. Additional details of separation zone 14 andgasification system 17 are provided below.

In another embodiment, hydrocatalytic treatment system 12 furthercomprises a digestion process to convert cellulose and other complexcarbohydrates contained in biomass feedstock 11 into a solublecarbohydrate. As used herein, the term “soluble carbohydrates” refers tomonosaccharides or polysaccharides that become solubilized in adigestion process. Any suitable digestion process that forms apretreated biomass containing soluble carbohydrates can be used.Examples of suitable digestion processes can be found in U.S.Application Publication Nos. US2012/0152836, and US2012/0156743, thedisclosure of each is incorporated herein by reference in its entirety.

In one embodiment, hydrocatalytic treatment system 12 can comprise areaction as described in US2012/0152836. For instance, hydrocatalytictreatment system 12 can comprise any combination of hydrogenolysissystems 126, 126A, 126B, and 126C shown in FIGS. 1-5 of US2012/0152836.In another embodiment, hydrocatalytic treatment system 12 can furthercomprise digestion system 106 shown in FIGS. 1-5 of US2012/0152836. Thedescriptions corresponding to digestion system 106 and hydrogenolysissystems 126, 126A, 126B, and 126C are provided by US2012/0152836, whichis incorporated by reference in its entirety, and thus need not berepeated. In such embodiments, at least a portion of any product streamexiting a hydrogenolysis system, such as stream 122, stream 123, orstream 130, of FIGS. 1-5 of US2012/0152836 can be routed to separationzone 14 shown in FIGS. 1-2, so a bottom fraction 16 can be separatedfrom the products stream and gasified as described herein.

In another embodiment, hydrocatalytic treatment system 12 can comprise areaction as described in US2012/0156743. For instance, hydrocatalytictreatment system 12 can comprise hydrogenolysis system 120 shown inFIGS. 1-2 of US2012/0156743. In another embodiment, hydrocatalytictreatment system 12 can further comprise pretreat system 104, optionallyalong with digestive system 190, and/or treatment system 110 of FIGS.1-2 of US2012/0156743. In such embodiments, at least a portion ofoxygenated intermediate stream 122 of FIGS. 1-2 of US2012/0156743 can berouted to separation zone 14 shown in FIGS. 1-2, so a bottom fraction 16can be separated from the products stream and gasified as describedherein.

It is understood that the hydrocatalytic treatment that takes place inhydrocatalytic treatment system 12 can employ aqueous phase and/ororganic phase solvents. For example, US2011/0154721, US2012/0152836, andUS2012/0156743 provide examples of hydrocatalytic treatment that occursin aqueous phase. Exemplary descriptions of a hydrocatalytic treatmentthat takes place in an organic phase can be found in U.S. ApplicationPublication No. US2013/0109896, the disclosure of which is herebyincorporated by reference in its entirety.

In one embodiment, hydrocatalytic treatment system 12 can comprise areaction as described in US2013/0109896. For example, hydrocatalytictreatment system 12 can comprise organic phase hydrocatalytic treatmentsystem 20 shown in FIG. 1 of US2013/0109896. In another embodiment,hydrocatalytic treatment system 12 can further comprise digestive system10 shown in FIG. 1 of US2013/0109896. The descriptions corresponding todigestive system 10 and organic phase hydrocatalytic treatment system 20are provided by US2013/0109896, which is incorporated by reference inits entirety, and thus need not be repeated. In such embodiments, atleast a portion of organic hydrocarbon-rich phase stream 32 shown inFIG. 1 of US2013/0109896 can be routed to separation zone 14 shown inFIGS. 1-2, so a bottom fraction 16 can be separated from the organichydrocarbon-rich phase stream 32 and gasified as described. In oneembodiment, the liquid-liquid separation 30 in FIG. 1 of US2013/0109896can be part of separation zone 14. That is, separation zone 14 cancomprise the liquid-liquid separation 30 in FIG. 1 of US2013/0109896.For example, in one embodiment, separation zone 14 comprises aliquid-liquid separation step, such as that described in US2013/0109896,which provides bottom fraction 16 that can be routed to gasificationsystem 17. In addition to or as an alternative, in one embodiment, theliquid-liquid separation step provides an organic hydrocarbon-rich phasethat is further separated in separation zone 14 to provide bottomfraction 16.

In yet another embodiment, if a digestion process is employed, thedigestion process preferably comprises hydrothermal digestion,particularly as described in U.S. Application Publication Nos.61/665,641, filed on Jun. 28, 2012, 61/720,757, filed on Oct. 31, 2012,and 61/817,996, filed on May 1, 2013, the disclosures of which arehereby incorporated by reference in their entirety. Hydrothermaldigestion of biomass feedstock 11 is preferably conducted in thepresence of molecular hydrogen and a slurry catalyst capable ofactivating the molecular hydrogen. In such particular embodiments, thehydrothermal digestion of cellulosic biomass and the catalytic reductionof soluble carbohydrates produced therefrom preferably take place in thesame vessel, which can be referred to as “in situ catalytic reductionreaction processes.” As used herein, the term “slurry catalyst” willrefer to a catalyst comprising fluidly mobile catalyst particles thatcan be at least partially suspended in a fluid phase via gas flow,liquid flow, mechanical agitation, or any combination thereof.

In one embodiment, hydrocatalytic treatment system 12 can comprise areaction as described in U.S. Application No. 61/665,641. For example,hydrocatalytic treatment system 12 can comprise at least one ofhydrothermal digestion unit 2 and catalytic reduction reactor unit 4shown in FIG. 1 of U.S. Application No. 61/665,641. In anotherembodiment, hydrocatalytic treatment system 12 can further comprisesolids separation mechanism 24 also shown in FIG. 1 of U.S. ApplicationNo. 61/665,641. Solids separation mechanism 24 can comprise any suitablemechanism that can remove at least a solid contained in a product streamexiting catalytic reduction reactor unit 4, such as reaction producttakeoff line 18 shown in FIG. 1 of U.S. application Ser. No. 61/665,641.Non-limiting examples of suitable solids separation mechanisms mayinclude, for example, any number and combination of filters,hydroclones, centrifuges, membranes, and settling tanks. Thedescriptions corresponding to hydrothermal digestion unit 2, catalyticreduction reactor unit 4, and solids separation mechanism 24 areprovided by U.S. Application No. 61/665,641, which is incorporated byreference in its entirety, and thus need not be repeated. In suchembodiments, at least a portion of reaction product takeoff line 18shown in FIG. 1 of U.S. Application No. 61/665,641, whether havingpassed through solids separation mechanism 24, can be routed toseparation zone 14 shown in FIGS. 1-2, so a bottom fraction 16 can beseparated and gasified as described. In one embodiment, phase separationmechanism 26 in FIG. 1 of U.S. application Ser. No. 61/665,641 can bepart of separation zone 14. That is, separation zone 14 can comprisephase separation mechanism 26 in FIG. 1 of U.S. Application No.61/665,641 that provides bottom fraction 16 which can be routed togasification system 17. In addition to or alternatively, in oneembodiment, phase separation mechanism 26 in FIG. 1 of U.S. ApplicationNo. 61/665,641 provides an organic phase that is further separated inseparation zone 14 to provide bottom fraction 16.

In another embodiment, hydrocatalytic treatment system 12 can comprise areaction as described in U.S. Application No. 61/720,757. For example,hydrocatalytic treatment system 12 can comprise at least one ofhydrothermal digestion unit 2 and polishing reactor 16 shown in FIG. 1of U.S. Application No. 61/720,757. If employed, polishing reactor 16shown in FIG. 1 of U.S. Application No. 61/720,757 is where one or morecatalytic reduction reactions can further take place to protect solublecarbohydrates from thermal degradation as described. The descriptionscorresponding to hydrothermal digestion unit 2 and polishing reactor 16are provided by U.S. Application No. 61/720,757, which is incorporatedby reference in its entirety, and thus need not be repeated. In suchembodiments, at least a portion of lignin removal line 18 shown in FIG.1 of U.S. Application No. 61/720,757 can be routed to separation zone 14shown in FIGS. 1-2, so a bottom fraction 16 can be separated andgasified as described. In addition to or alternatively, in embodimentscomprising polishing reactor 16 shown in FIG. 1 of U.S. Application No.61/720,757, at least a portion of the product stream exiting polishingreactor 16 can be routed to separation zone 14 shown in FIGS. 1-2, so abottom fraction 16 can be separated and gasified as described. That is,the input to separation zone 14 can include a product from hydrothermaldigestion unit 2 and/or polishing reactor 16 of U.S. Application No.61/720,757.

In yet another embodiment, hydrocatalytic treatment system 12 cancomprise a reaction as described in U.S. Application No. 61/817,996. Forexample, hydrocatalytic treatment system 12 can comprise at least one ofhydrothermal digestion unit 2 and polishing reactor 16 shown in FIGS.1-12 of U.S. Application No. 61/817,996. If employed, polishing reactor16 shown in FIGS. 1-12 of U.S. Application No. 61/817,996 is where oneor more catalytic reduction reactions can further take place to protectsoluble carbohydrates from thermal degradation as described. Thedescriptions corresponding to hydrothermal digestion unit 2 andpolishing reactor 16 are provided by U.S. application Ser. No.61/817,996, which is incorporated by reference in its entirety, and thusneed not be repeated. In such embodiments, at least a portion of ligninremoval line 18 shown in FIGS. 1-12 of U.S. Application No. 61/817,996can be routed to separation zone 14 shown in FIGS. 1-2, so a bottomfraction 16 can be separated and gasified as described. In addition toor alternatively, in embodiments comprising polishing reactor 16 shownin FIGS. 1-12 of U.S. Application No. 61/817,996, at least a portion ofthe product stream exiting polishing reactor 16 can be routed toseparation zone 14 shown in FIGS. 1-2, so a bottom fraction 16 can beseparated and gasified as described. That is, the input to separationzone 14 can include a product from hydrothermal digestion unit 2 andpolishing reactor 16 of U.S. Application No. 61/817,996. In oneembodiment, separations unit 32 in FIGS. 1-12 of U.S. Application No.61/817,996 can be part of separation zone 14. That is, separation zone14 can comprise separations unit 32 in FIGS. 1-12 of U.S. ApplicationNo. 61/817,996 that provides bottom fraction 16 which can be routed togasification system 17.

Referring to FIGS. 1-2, at least a portion of hydrocatalytically treatedmixture 13 formed in hydrocatalytic treatment system 12 is routed toseparation zone 14 where mixture 13 can be separated into differentcomponents that can be further processed accordingly. In a preferredembodiment, at least a portion of hydrocatalytically treated mixture 13is separated into at least two fractions in separation zone 14: overheadfraction 15 and bottom fraction 16. In one embodiment, separation zone14 can comprise a phase separator, a stripping column, an extractor, afilter, a distillation column, a flasher, or any combination thereof.

In a preferred embodiment, separation zone 14 separateshydrocatalytically treated mixture 13 into various components based onthe volatility property (separation point) of the compounds in mixture13 under various temperature and pressure conditions. For example, atemperature in a range of about 100 to 600 degrees C. and a pressure ofabout atmospheric pressure, more preferably a temperature in a range ofabout 100 to 500 degrees C. and a pressure in a range of about 1 to 100Torr, preferably about 3 to 20 Torr; most preferably a temperature in arange of about 200 to 450 degrees C. and a pressure in a range of about1 to 100 Torr, preferably about 3 to 20 Torr, can be applied to at leasta portion of hydrocatalytically treated mixture 13. Referring to FIGS.1-2, in one embodiment, compounds that vaporize under these conditionsbecome overhead fraction 15, which can be collected for furtherprocessing, and compounds that do not vaporize remain to form bottomfraction 16. The temperature and pressure can be applied gradually in acontinuous or step-wise manner or rapidly as desired or according tooperating conditions using suitable techniques known to those skilled inthe art, such as those employed in distillation columns. The temperatureand pressure can be applied for any suitable duration. Such manners ofapplying temperature and pressure to separate components based onvaporization properties are known to those skilled in the art. Examplesof a suitable time period include about 1-60 minutes. Bottom fraction 16preferably comprises lignin and/or lignin-derived compounds, such aspartially depolymerized lignin moieties containing 5-′5, phenylcoumaran,and β-O-4 linkages as characterized by monomeric compounds phenol,o-cresol, p-cresol, anisole, 4-methylanisole, catechol, guaiacol,4-methylguaiacol, 1,3-dimethoxybenzene, syringol, and vanillin. Otherderived compounds include methanol, methoxyphenol, methyl phenol,dimethyl phenol, ethyl phenol, methyl ethyl phenol, methoxypropylphenol,benzene diol, propyl phenol, and similar compounds. In a preferredembodiment, bottom fraction 16 is a solid at ambient temperature and canflow at higher temperatures, such as greater than 100 degrees C. Theviscosity of bottom fraction 16 preferably decreases with increasingtemperature. In one embodiment, the viscosity of bottom fraction 16 at atemperature of about 75 degrees C. is preferably about 1 to 10,000centipoise (cP), more preferably about 100 to 5,000 cP, most preferablyabout 500 to 1000 cP. As will be understood by those of ordinary skillin the art, the viscosity and therefore the pumpability of bottomfraction 16 from separation zone 14 and/or bottom fraction 26 fromseparation zone 24 can be affected by various factors, includingtemperature, pressure, concentration of various compounds in theparticular bottom fraction, composition, diluents, if any are used,impurity levels, storage time. If the physical state of bottom fraction16 and/or bottom fraction 26 is solid to viscous, or a semi-solidliquid, it can be heated to a temperature and/or the pressure suitableto render it sufficiently fluid to be pumped, as desired.

Overhead fraction 15 is preferably subject to further processing toproduce a higher molecular weight compound. In one embodiment, thefurther processing takes place in processing zone 22 shown in FIG. 2.Non-limiting exemplary further processing methods include (i) reformingreactor 38 shown in FIGS. 1-12 of U.S. Application No. 61/817,996, (ii)reforming reactor 28 shown in FIG. 1 of U.S. Application No. 61/720,757,(iii) processing system 130 shown in FIGS. 1-2 of US2012/0156743, (iv)processing step 136 shown in FIGS. 1-5 of US2012/0152836; and processingreaction 110 shown in FIGS. 1-3 of US2011/0154721. In general, suitablefurther processing reactions include, but are not limited to,hydrogenolysis reactions, hydrogenation reactions, condensationreactions, isomerization reactions, oligomerization reactions,hydrotreating reactions, alkylation reactions, and any combinationthereof. For example, referring to FIG. 2, overhead fraction 15 issubject to a condensation reaction in processing zone 22 to produceproduct stream 23, which is routed to separation zone 24 where productstream 23 can be fractionated into desired components.

The further processing can comprise one or more reactions that may becatalytic or non-catalytic. It is to be understood that any number ofreactors may be employed to carry out the further processing, such asthat in processing zone 22. In some embodiments, a first furtherprocessing reaction may comprise a condensation reaction. Additionalfurther processing reactions may comprise any combination of furthercatalytic reduction reactions (e.g., hydrogenation reactions,hydrogenolysis reactions, hydrotreating reactions, and the like),further condensation reactions, isomerization reactions, desulfurizationreactions, dehydration reactions, oligomerization reactions, alkylationreactions, and the like. Such reactions may be used to convert theinitially produced soluble carbohydrates into a biofuel, including, forexample, gasoline hydrocarbons, diesel fuels, jet fuels, and the like.As used herein, the term “gasoline hydrocarbons” refers to substancescomprising predominantly C₅-C₉ hydrocarbons and having a boiling pointof about 32 to 204 degrees C. More generally, any fuel blend meeting therequirements of ASTM D2887 may be classified as a gasoline hydrocarbon.Suitable gasoline hydrocarbons may include, for example, straight rungasoline, naphtha, fluidized or thermally catalytically crackedgasoline, VB gasoline, and coker gasoline. As used herein, the term“diesel fuel” refers to substances comprising paraffinic hydrocarbonsand having a boiling point in a range of about 187 to 417 degrees C.,which is suitable for use in a compression ignition engine. Moregenerally, any fuel blend meeting the requirements of ASTM D975 may alsobe defined as a diesel fuel. As used herein, the term “jet fuel” refersto substances meeting the requirements of ASTM D1655. In someembodiments, jet fuels may comprise a kerosene-type fuel havingsubstantially C₈-C₁₆ hydrocarbons (Jet A and Jet A-1 fuels). In otherembodiments, jet fuels may comprise a wide-cut or naphtha-type fuelhaving substantially C₅-C₁₅ hydrocarbons present therein (Jet B fuels).

In another embodiment, the products of a further processing reaction canbe separated further to produce a second overhead fraction and a secondbottom fraction which can be gasified in gasification system 17. Asshown in FIG. 2, at least a portion of overhead fraction 15 is routed toprocessing zone 22 to form higher molecular weight compounds, which exitprocessing zone 22 as product stream 23. In one embodiment, at least aportion of product stream 23 is routed to separation zone 24 for furtherseparation, preferably into at least two fractions: overhead fraction 25and bottom fraction 26. In a preferred embodiment, a first fractionexiting separation zone 24 is overhead fraction 25 comprising compoundsthat vaporize at a separation point of bottom fraction 26. A secondfraction exiting separation zone 24 is preferably bottom fraction 26comprising compounds having a separation point having a temperature in arange of about 100 to 500 degrees C., more preferably a temperature in arange of about 150 to 400 degrees C., and most preferably in a range ofabout 200 to 400 degrees C., and a pressure in a range of about 0.10 to7 bar. In addition to or alternatively to bottom fraction 16, in oneembodiment, at least a fraction of bottom fraction 26 entersgasification system 17 to be partially oxidized and routed tohydrocatalytic treatment system 12 as described in this disclosure.Separation zone 24 preferably functions similar to separation 14 wherecomponents can be separated based on their vaporization properties. Forinstance, overhead fraction 25 and bottom fraction 26 can be generatedfrom application of a temperature in a range of about 100 to 500 degreesC. and a pressure in a range of about 0.10 to 7 bar. Compounds thatwould vaporize at the applied temperature and pressure can form overheadfraction 25, which can be collected for further processing or other use.Compounds that would not vaporize at the applied temperature andpressure remain to form bottom fraction 26. Bottom fraction 26preferably comprises C₁₄ or greater hydrocarbons, including an olefin, aparaffin, an aromatic, or a cycloalkane.

Referring to FIGS. 1-2, at least one of a portion of bottom fraction 16and a portion of bottom fraction 26 is routed to gasification system 17where it serves as a carbonaceous feed. It is understood that thetemperature and pressure under which bottom fraction 16 and/or bottomfraction 26 enter gasification system 17 are dependent on thegasifier(s) selected as discussed further below.

In gasification system 17, bottom fraction 16 is partially oxidized toproduce gas mixture 19 which comprises hydrogen (H₂) and carbon monoxide(CO). Bottom fraction 16 can enter gasification system 17 in any form,such as a dry feed or a wet feed, including a solid, a liquid, or asolid coated with a liquid. The term “liquid” used in context of bottomfraction 16 and/or bottom fraction 26 refers to a carbonaceous feed thatis a liquid, an emulsion, or a pumpable slurry at the feed pressure andtemperature into gasification system 17. In a preferred embodiment,bottom fraction 16 and/or bottom fraction 26 enters gasification system17 as a liquid.

Gasification system 17 can comprise any suitable gasification systemthat can partially oxidize bottom fraction 16 and/or bottom fraction 26to generate gas mixture 19. For example, in one embodiment, if bottomfraction 16 enters gasification system 17 as a solid, any suitable dryfeed gasification system can be used to partially oxidize bottomfraction 16 to produce gas mixture 19. In another embodiment, if bottomfraction 16 and/or bottom fraction 26 enters gasification system 17 as aliquid, any suitable wet feed gasification system can be used topartially oxidize bottom fraction 16 and/or bottom fraction 26 toproduce gas mixture 19. Dry feed and wet feed gasification systems areknown to those of ordinary skill in the art.

The gasification process is well known in the art and can be employedusing solid and liquid carbonaceous sources. The gasification processuses partial oxidation or incomplete combustion to convert carbonaceousmaterials at high temperature into synthesis gas (“syngas”), whichcomprises carbon monoxide and hydrogen. This is in contrast to a fullcombustion or complete oxidation reaction where primarily steam andcarbon dioxide are produced by the reaction of a fuel, such as acarbonaceous material, and an oxidant, such as oxygen. A completeoxidation typically take place under conditions that have excess oxygenaccording to the following equation:C_(n)H_(m)+(n+¼m)O₂→½mH₂O+nCO₂  Equation (1)

For gasification processes, oxygen is restricted to less than astoichiometric concentration of oxygen relative to fuel where processgenerates primarily hydrogen and carbon monoxide through incompletecombustion or partial oxidation of the fuel, as represented by theequation below:C_(n)H_(m)+½nO₂→½mH₂ +nCO  Equation (2)

The operating conditions, including temperature, vary with the gasifierand feed type as described further below. Gasification system 17 cancomprise a single gasifier, which can also be referred to asgasification reactor vessel, or two or more gasifiers of differ rent orthe same type arranged in series and/or parallel. One or more oxidantsand one or more feed, i.e., bottom fraction 16 and/or bottom fraction 26can be directed, fed, or otherwise introduced to one or more particulargasifier of gasification system 17. The one or more oxidants and one ormore feed can be introduced to gasification system 17 continuously,intermittently, interspersingly, simultaneously, separately,sequentially, or a combination thereof. Any number of oxidants can bedirected, fed, or otherwise introduced to gasification system 17. Forexample, the number of oxidants introduced to gasification system 17 canbe 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. It is understood thatconditions for partial oxidation or incomplete combustions may beprovided at least by limiting the amount of oxygen available ingasification system 17 to less than what is required for full oxidationor combustion. For example, this can be done by controlling the amountof oxidant stream 18 entering gasification system 17 and/or by theamount of oxygen in oxidant stream 18 itself.

Various types of gasifiers can be utilized as discussed and describedherein. In general, the gasifier types can be grouped into threeprincipal categories: moving-bed gasifiers, fluid-bed gasifiers, andentrained-flow gasifiers. Each of the three types can be used with solidcarbonaceous material. The entrained-flow gasifier can particularlyprocess liquid carbonaceous material efficiently. Exemplary commercialgasification providers include GE Energy, Conoco Philips E-Gas, Shell,Siemens, KBR Transport, and British Gas Lurgi (BGL). For example,gasification system 17 can entail one or more circulating solids ortransport gasifiers, one or more fixed bed gasifiers, one or morefluidized bed gasifiers, one or more entrained flow gasifiers, or acombination thereof. An exemplary gasifier suitable for use according toone or more embodiments discussed and described herein, particularlywhen bottom fraction 16 and/or bottom fraction 26 enter gasificationsystem 17 as a liquid, can be a gasifier configured according to theShell Gasification Process (SGP) as known to those skilled in the art.

In general, moving-bed gasifiers, which can also be called fixed-bedgasifiers in certain instances, have a bed on which the dry or solidfeed moves downward under gravity as it is gasified by flow of oxidantto generate synthesis gas. In one embodiment, the oxidant flow iscounter-current to the movement of the feed. In such an embodiment, thehot synthesis gas generated is preferably used to preheat and pyrolysethe downward flowing coal. In one embodiment, the size of feed enteringa moving-bed gasifier, if one is used, is in a range of about 6 to 50mm. In another embodiment, the outlet gas temperature of a moving-bedgasifier is in a range of about 425 to 650 degrees C.

FIG. 3 provides one non-limiting exemplary embodiment of a moving-bed orfixed-bed gasifier with reference numeral 300, such as a Sasol-Lurgigasifer. Gasifier 300 includes feed lock 302, reactor vessel 304, grate306, and ash lock 308. In operation of one embodiment, a sized solidfeed 310 comprising bottom fraction 16 and/or bottom fraction 26, withparticles preferably greater than about 4 mm, preferably in a range ofabout 6 to 50 mm, enters reactor vessel 304 through feed lock 302 andmoves down through a bed formed inside reactor vessel 304. Oxygen stream312 and steam 314 enter at a bottom of the bed, through grate 306. In apreferred embodiment, oxygen stream 312 and steam 314 corresponds tooxidant stream 18 of FIGS. 1 and 2. In the embodiment shown, oxygenstream 312 and steam 314 combine with each other before entering reactorvessel 304. In one embodiment, gasifier 300 can be a pressurizedgasifier, where oxygen stream 312 and steam 314 have a pressure of about20 bar or more.

In one embodiment, reactor vessel 304 has different reaction zonesdistinguishable from top to bottom, starting with a drying zone wheremoisture is released, below which is a devolatization zone wherepyrolysis takes place, below which is a reduction zone or gasificationzone where mainly endothermic reactions occur, below which is anexothermic oxidation or combustion zone, and an ash bed at the bottom ofreactor vessel 304. It is understood that the transition from one zoneto the next is gradual. As shown in FIG. 3, gasifier 300 is operated ina counter-current mode where oxygen stream 312, steam 314, and syngasflow upwards counter-current to the movement of feed 310. In such anembodiment, higher temperature ash exchanges heat with lower temperatureincoming reagents, such as oxygen stream 312, steam 314, or air, whileat the same time higher temperature synthesis gas exchanges heat withlower temperature incoming feed 310. As shown in FIG. 3, synthesis gasstream 320 exits gasifier 300 near a top of reactor vessel 304. Ashgenerated in reactor vessel 304 passes through grate 306 and the ashlock 308 before it exits gasifier 300 as ash stream 316.

In one embodiment, the temperature profile in gasifier 300 can varybetween about 800 and 1200 degrees C., such as at least 1000 degrees C.,as feed 310 moves through the different zones in reactor vessel 304. Inanother embodiment, the temperature profile in gasifier 300 can be up toabout 1700 degrees C. In one embodiment, synthesis gas stream 30 leavesgasifier 300 at a temperature in the range of 375 to 650 degrees C. Itis understood by one of ordinary skill in the art that it is typicallydifficult for a moving-bed or fixed-bed gasifier, such as gasifier 300,to handle high melting ash. In one embodiment, the operating conditionscan be adjusted accordingly.

With respect to the second type of gasifier, fluid-bed gasifiers, ingeneral, provide conditions that promote mixing between feed andoxidant, thereby ensuring an even distribution of material in the bed.Fluid-bed gasifier technology is generally based on the velocity of theflow of gas (oxidant and syngas) through the reactor. The lower range ofgas velocity includes a stationary or bubbling fluid bed reactor wherethe gas velocity is low enough to provide a distinction between thedense phase or bed and the freeboard where the solid particles from thefeed disengage from the flow of gas. As the gas velocity increases, thehigher range of gas velocity includes a transport reactor where all thesolid particles are carried with the gas and full pneumatic transport isachieved. The region between the two ends of the gas velocities spectrumincludes a circulating fluid bed reactor where the differential velocitybetween gas and solids reaches a maximum at intermediate gas velocities.In general, operation of a fluid-bed gasifier depends on the size offeed, which should be in a range where the particles of feed can belifted by the flow of gas. In one embodiment, the size of feed enteringa fluid-bed gasifier, if one is used, is in a range of about 6 to 10 mm.In another embodiment, the operating temperature of a fluid-bed gasifieris below the softening point of ash, which is typically, in oneembodiment, in a range between about 800 to 1100 degrees C. such asabout 1000 degrees C. In another embodiment, the operating temperatureis up to about 1700 degrees C. In yet another embodiment, the outlet gastemperature of a fluid-bed gasifier is in a range of about 750 to 1050degrees C. It is understood by one of ordinary skill in the art that itis typically difficult for a fluidized-bed gasifier, such as gasifiers400, 500, or 600, to handle high melting ash. In one embodiment, theoperating conditions can be adjusted accordingly.

FIG. 4 provides one non-limiting; exemplary embodiment of a bubbling orstationary fluidized bed gasification gasifier with numeral reference400. As shown, gasifier 400 comprises reactor vessel 402, having productgas outlet 403 disposed at or near its upper portion, feed inlet 404,reagent inlet 405 at or near a lower portion of reactor vessel 402, andfluidized bed 406 having a bed height 407 extending from a bottom ofreactor vessel 402 to a position in reactor vessel 402, and ashdischarge 409 at or near a bottom of reactor vessel 402.

During operation of gasifier 400, feed material 410 comprising bottomfraction 16 and/or bottom fraction 26 enters reactor vessel 402 throughfeed inlet 404, which preferably comprises a fluidizing nozzle toproduce particles having an appropriate or desired size. In oneembodiment, feed particles that enter reactor vessel 402 have a size ina range of about 6 to 10 mm. Oxidant, such as, air, oxygen, or steamenters reactor vessel 402 through reagent inlet 405. In addition to oras an alternative, feed material 410 can also enter reactor vessel 402through reagent inlet 405. In one embodiment, reagent inlet 405corresponds to oxidant stream 18 of FIGS. 1 and 2. Introduction of feedmaterial 410 and oxidant creates fluidized bed 407 in reactor vessel402. Ash created in the gasification process is discharged through ashdischarge 409, and synthesis gas generated in the gasification processis discharged through product gas outlet 403. The height of fluidizedbed 407 will vary, depending on such factors as reactor vesseltemperature and pressure and input rates of feed inlet 404 and reagentinlet 405, and discharge rates of ash discharge 409 and product gasoutlet 403. In one embodiment, the flow of gas through reactor vessel402 is configured to allow fluidized bed 407 to form.

In one embodiment, a circulating fluid bed comprises a centrifugalseparator, generally a cyclone separator to separate and recirculate aportion of the solid particles, which are contained in the gas exiting areactor vessel, back to the reactor vessel where feed material isgasified. In a preferred embodiment, the separated solid particles arefluidized prior to their recirculation into the reactor vessel topromote even distribution over the width of the fluidized bed in thereactor vessel. FIG. 5 provides one non-limiting exemplary embodiment ofcirculating fluidized bed gasifier with numeral reference 500. Gasifier500 comprises reactor vessel 502, oxidant inlet 506 and feed inlet 532,which are disposed near a bottom portion of reactor vessel 502, andseparator 508 coupled with an upper portion of reactor vessel 502 viaopening 510. There can be one or more separators. Separator 508preferably comprises a cyclone separator. As shown, separator 508comprises chamber 512, which is coupled to standpipe 514, which itselfis coupled to riser 516 through horizontal channel 518. As shown, riser516 is coupled to riser 520 through inclined channel 522, and riser 520in turn is coupled to reactor chamber 502 through inclined channel 524.Standpipe 514, riser 516, and horizontal channel 518 form asiphon-trap-like gas seal. In an alternative embodiment, inclinedchannel 522 and riser 520 can be omitted so that riser 516 can becoupled directly to reactor vessel 502 through inclined channel 524.

During operation, oxidant 504 enters reactor vessel 502 via oxidantinlet 506. Feed 530 comprising bottom fraction 16 and/or bottom fraction26 enters reactor vessel 502 through feed inlet 532. Gasification offeed 530 takes place in reactor vessel 502 when oxidant 504 and feed 530mix with one another. Gas comprising syngas and other reactants andproducts and entrained with solid particles in reactor vessel 502 moveupward toward and through opening 510 and into separator 508. Separator508 separates gas exiting reactor vessel 502 from the solid particles.Separated gas 536 exits gasifier 500 through outlet 538. The remainingsolid particles are moved through standpipe 514, risers 516 and 520,horizontal channel 518, and inclined channels 522 and 524. Thearrangement of standpipe 514, risers 516 and 520, horizontal channel518, and inclined channels 522 and 524 allows solid particles to returnto reactor chamber 502 and prevents unwanted escape of gas from reactorvessel 502 through opening 526 in the direction of cyclone separator508.

To ensure that solids collected in the region of the gas seal formed bystandpipe 514, riser 516, and horizontal channel 518 do not becomecompacted and deposited, fluidizing gas or air is supplied by means offluidizing device 528 providing flow essentially from beneath horizontalchannel 518. Ash 534 formed during gasification is discharged fromgasifier 500 through or near a bottom portion of reactor vessel 502.

In one embodiment, the velocity of gas flowing through gasifier 500 isin a range of about 5 to 8 m/s or another other suitable velocity thatcan ensure most of the solid particles in reactor vessel 502 areentrained and flow upward to leave reactor vessel 502. In oneembodiment, oxidant 504 can be fed as primary air into reactor vessel502 below nozzle grate 540.

FIG. 6 provides one non-limiting exemplary embodiment of a transportfluid bed gasifier with numeral reference 600. Gasifier 600 comprises ariser 602 above mixing zone 604. As shown, mixing zone 604 includespartial oxidation zone 606 wherein recirculating particulates areoxidized to form a high velocity stream of products (primarily carbonmonoxide) and finely divided particles,

Oxidant is introduced to partial oxidation zone 606 through inlet 608.Oxidant is generally fed at a rate suitable to control the temperatureof partial oxidation zone 606 and riser 12. Gasifier 600 furthercomprises feed injection zone 610, which is preferably disposed inmixing zone 604 above partial oxidation zone 606. Feed comprising bottomfraction 16 and/or bottom fraction 26 is injected through feed stream612 into feed injection zone 610 and mixed with the high velocity streamof effluents and particles from partial oxidation zone 606.

Feed stream 612 can be introduced as a solution, slurry, emulsion,suspension, etc. of solids, liquids or gases depending on the state ofbottom fraction 16 and/or bottom fraction 26 to be converted. Typically,solid can be dissolved and/or suspended in a hydrocarbon carrier liquidfor ease of handling and pumping. Feed in feed stream 612 can beintroduced to feed injection zone 610 and/or mixing zone 604 in stagesas desired depending, in part, on the composition of the feed,composition of the reaction effluent gas and process parameters ofgasifier 600 to ensure suitable operation thereof.

Steam is preferably injected into mixing zone 604 above feed injectionzone 610 via inlet 616. Alternatively and/or additionally, steam can beinjected with the feed. Steam can also be injected with oxidant instream 608. The effluents of mixing zone 604 are passed under reducingconditions through the riser 602 where steam reacts with carbon and thefeed to form hydrogen and carbon monoxide.

The high velocity partial oxidation products induce a rapid internalrecirculation flow of carrier particles in riser 602 which act like athermal flywheel to efficiently transfer heat from partial oxidationzone 606 to adiabatic pyrolysis zone 620 in riser 602 to supply heat forthe endothermic gasification. Materials suitable for use as carrierparticles circulating in gasifier 600 are finely divided refractorymaterials Which have a large surface area and are generally inert at thereaction conditions of the present process. Examples are particulatedalumina and silica, and spent catalyst from a fluidized catalyticcracking (FCC) reactor.

The reaction effluent from riser 602 passes into separation zone 622where carrier particles are recovered from the reaction effluent to givegas stream 636 that is essentially free of particulates. Separation zone622 preferably comprises one or more high efficiency cyclone separationstages. Particle-laden reaction effluent from riser 602 is fed tocyclone 624 through line 626. Additional secondary cyclone separators(not shown) can be used if required.

Cyclone 624 is coupled to dipleg 628 having particles holdup zone 630for increasing the residence time of the carrier particles, if desired,and transfer line 632 for conveying the particles to partial oxidationzone 606 at a rate sufficient to sustain continuous operation of thepartial oxidation zone 606 and feed injection zone 610. Separation zone622 further comprises bleed line 634 through which a portion of thesolids from holdup zone 630 can be bled from gasifier 600 to maintain adesired maximum concentration of metals on the solids.

Depending on the design operating pressure, gasifier 600 can operate ata temperature suitable for promoting gasification without the need forany catalytic activity of the circulating carrier particles.Gasification can typically commence at a temperature as low as about 650degrees C. Preferably, gasifier 600 operates in a temperature range ofabout 750 to 1050 degrees C., measured at an outlet of riser 602. Theoperating temperature range is generally controlled by specifying therate of oxidant supply to partial oxidation zone 606 and the rate ofcarrier recirculation. Gasifier 600 can be designed to operate at anelevated pressure, up to about 4.0 MPa (about 600 psig), to increasehandling capacity per unit reactor cross-sectional area.

With respect to the third type of gasifier, in general, entrained-flowgasifiers operate with the flow of feed and flow of thermal energy in aco-current manner. In a preferred embodiment, the residence time whenthe feed and thermal energy flow contact one another is in a range ofabout 0.1 to 20 seconds. If the feed is solid, it is formatted to a sizeof about less than 100 μm to promote mass transfer and allow transportin the gas. Entrained-flow gasifiers can handle a wide range of feedmaterials. The gasification usually takes place in a combustion chamberwhich operates at a temperature in the range of about 800 to 1700degrees C., preferably about 1000 to 1700 degrees C., and at a pressurein the range of about 20 to 70 bar. In another embodiment, the outletgas temperature of an entrained-flow gasifier is in a range of about1250 to 1600 degrees C.

In general, entrained-flow gasifiers can have various configurationsbased on a combination of the location of the burner(s) and the liningof the gasifier. An entrained-flow gasifier can have one or more burnerspreferably located in the top portion or near a bottom portion of areactor chamber. Further, an entrained-flow gasifier can comprise arefractory lined wall or a membrane wall. The refractory lined wall isconfigured to protect a reactor vessel from corrosive slag, thermalcycling. The membrane wall performs a similar function using a coolingscreen protected by a layer of refractory material to provide a surfaceon which the molten slag solidifies and flows downwardly to the quenchzone at the bottom of the reactor. In one embodiment, if bottom fraction16 and/or bottom fraction 26 is fed to gasification system 17 as a dryfeed, at least one gasifier in accordance with Shell Coal GasificationProcess (SCGP) can be used. In another embodiment, if bottom fraction 16and/or bottom fraction 26 is fed to gasification system 17 as a liquidfeed, at least one gasifier in accordance with Shell GasificationProcess (SGP) can be used. It is understood that the choice between arefractory lined gasifier and a membrane wall gasifier is determined bythe ash properties of the feed as known to those skilled in the art.That is, a dry feed can be gasified using a gasifier in accordance withShell Gasification Process (SGP), and a liquid feed can be gasifiedusing a gasifier in accordance with Shell Coal Gasification Process(SCGP).

FIG. 7 provides one non-limiting exemplary embodiment an entrained flowgasifier having numeral reference 700. Gasifier 700 has a similarconfiguration to that of a gasifier that can be used in the Shell CoalGasification Process (SCEP). As shown, gasifier 700 has pressure shell702, membrane wall 704 and reaction zone 706. In one embodiment,membrane wall 704 is composed of vertical conduits through which coolingfluid flows. The cooling fluid is preferably water. The cooling fluid issupplied to membrane wall 704 via supply line 708 to distributor 710.The used cooling fluid is discharged from gasifier 700 via common header712 and discharge line 714. Gasifier 700 is further provided with quenchgas supply 716, discharge line 718 for the product gas mixture,including syngas, generated in reaction zone 706, and discharge line 720for slag. Gasifier 700 further comprises a layer of refractory materialcoupled to membrane wall 704 to further protect pressure shell 702 fromthe high temperature of reaction zone 706. Pressure shell 702 maycomprise any suitable material, such as, for example, steel.Non-limiting examples of a suitable refractory material can includealloys of silica, alumina, iron, chromium, zirconium, and/or other hightemperature materials.

As shown, gasifier 700 comprises at least two diametrically opposedburners 722 through which feed comprising bottom fraction 26 and/orbottom fraction 16 is introduced to reaction zone 706. Gasifier 700 cancomprise any number of pairs of burners 722, for example, two or morepairs of such burners at the same elevation, or alternatively atdifferent elevations. In a preferred embodiment, burners 722 aredisposed near a bottom portion of gasifier 700. Any suitable burner canbe used. Non-limiting exemplary suitable burners for a solid feed are,for example, described in U.S. Pat. No. 4,523,529 and U.S. Pat. No.4,510,874. As shown, burners 722 are fed by feed supply line 724 andoxidant supply line 726, which are preferably mixed before being fed toburners 722. As shown, feed supply line 724 is mixed with oxidant supplyline 726 near a nozzle of burners 722. Syngas formed from thegasification process can exit gasifier 700 through discharge line 718,and slag formed from the gasification process can exit gasifier 700through discharge line 720.

In one embodiment, feed can be pulverized to a desired size andtransported through feed supply line 724 as a dense phase in an inertgas (such as nitrogen or carbon dioxide), acting as a carrier gas. Inanother embodiment, viscous liquid feed can also be used.

During operation, feed mixed with oxidant is introduced to reaction zone706 through burners 722. The reactions taking place in reaction zone 706occurs rapidly, in a range of about 0.5 to 4 seconds. Product gas leavesgasifier 700 through discharge line 718, and slag leaves throughdischarge line 720 at or near the bottom of gasifier 700 where it isquenched in a water bath. In one embodiment, the operating temperatureof gasifier 700 is about at least about 1000 degrees C. and theoperating pressure of gasifier 700 is in a range of about 15 to 80 bar,preferably in a range of about 25 to 45 bar.

FIG. 8 provides one non-limiting exemplary embodiment an entrained flowgasifier having numeral reference 800. Gasifier 800 has a similarconfiguration to that of a gasifier that can be used in the ShellGasification Process (SUP). As shown, gasifier 800 comprises pressureshell 802, refractory liner 804 and reaction zone 806. Pressure shell802 may comprise any suitable material, such as, for example, steel.Non-limiting examples of a suitable refractory material for use asrefractory liner 804 can include alloys of silica, alumina, iron,chromium, zirconium, and/or other high temperature materials.

As shown, gasifier 800 comprises burner 808 disposed at or near a topportion of gasifier 800 preferably with its outlet directed downwardly.Feed 810 formed from bottom fraction 26 and/or bottom fraction 16 isintroduced to reaction zone 806 through burner 808. In a preferredembodiment, gasifier 800 comprises one burner. Any suitable burner canbe used. Non-limiting exemplary suitable burners for a solid feed are,for example, described in U.S. Pat. No. 4,523,529 and U.S. Pat. No.4,510,874. As shown, oxidant 812 and moderator gas 814 are also fed toburner 808 along with feed 810. The gasification product mixture isdischarged from gasifier 800 via discharge line 816.

During operation, feed 810 preferably mixed with oxidant 812 andoptionally moderator gas 814 is introduced to reaction zone 806 throughburner 808. The reactions taking place in reaction zone 806 occursrapidly, in a range of about 0.5 to 4 seconds. The product mixture isdischarged from gasifier 800 through discharge line 816. In oneembodiment, the operating temperature of gasifier 800 is about at leastabout 1300 degrees C. and the operating pressure of gasifier 800 is in arange of about 30 to 70 bar, preferably in a range of about 35 to 65bar.

FIG. 9A provides a cross sectional view of one non-limiting exemplaryembodiment an entrained flow gasifier having numeral reference 900. Likegasifier 700 of FIG. 7, gasifier 900 has a membrane lined wall; butunlike gasifier 700, the burner of gasifier 900 is located at or near atop portion of the gasifier. As shown, gasifier 900 comprises burner 902disposed at or near a top portion of gasifier 900, and burner 902 ispreferably with its outlet directed downwardly. In a preferredembodiment, burner 902 is provided with oxidant supply conduit 904, feedsupply conduit 906, and moderator gas supply conduit 908. Gasifier 900preferably comprises combustion chamber 910 in the upper half ofgasifier 900. As shown, combustion chamber 910 is provided with productgas outlet 912 at the bottom end and an opening for the outlet of theburner at its top end. Between combustion chamber 910 and the inner wallof pressure shell 912 is annular space 914. Combustion chamber 910comprises refractory layer 916 configured to reduce the heat transfer topressure shell 912. Refractory layer 916 is preferably coupled tocooling conduit 918 configured to cool refractory layer 916 by allowingwater to flow therethrough. In the embodiment shown, cooling conduit 918is arranged as a plurality of vertical tubes surrounding refractorylayer 916. FIG. 9B is a cross-sectional view taken along the line A-A′of FIG. 9A, which further depicts the vertical tubes of cooling conduit918. In another embodiment, conduits 918 may be arranged spirally woundaround refractory layer 916. Cooling conduit 918 can be coupled to theinner wall or outer wall of refractory layer 918. As shown, the verticaltubes of cooling conduit 918 may optionally have common header 920disposed at a top portion and common distributor 922 at a bottom portionfor discharging water from and supplying water to cooling conduit 918,respectively. Common header 920 is in fluid communication with steamdischarge conduit 924 and common distributor 922 is in fluidcommunication with water supply conduit 926. Annular space 914,refractory layer 916, and conduits 918 are configured to protectpressure shell 912 against the high temperatures of combustion chamber910. The vertical tubes of cooling conduit 918 shown in FIGS. 1 and 2can also be referred to as a membrane wall.

Cooling of refractory layer 916 by cooling conduit 918 may be achievedby heat exchange with water of a lower temperature entering commondistributor 922 and flowing through cooling conduit 918. Coupled toproduct gas outlet 912 is passage 928 configured to direct productmixture exiting combustion chamber 910 toward quenching zone 940, whichis disposed at or near a bottom portion of gasifier 900. Passage 928further comprises outlet 930 that allows the addition of a quenchingmedium to the product mixture leaving combustion chamber 910.

As shown, gasifier 900 further comprises pathway 932 that allows theproduct mixture to flow upward to exit gasifier 900 through outlet 934.Pathway 932 is preferably an annular space between passage 928 andintermediate wall 936. In FIG. 9A, space 938 between intermediate wall936 and pressure shell 912 holds water at level 938. Outlet 934 islocated above water level 938. Referring to FIG. 9A, quenching zone 940is contained in the space below the end of passage 928 and betweenintermediate wall 936 and a bottom portion of pressure shell 912.Quenching zone 940 also comprises slag generated from the gasificationprocess, which can be discharged from gasifier 900 via outlet 942.

In one embodiment where an entrained-flow gasifier is used, oxidant ispreheated and mixed with a moderator gas before the mixture is combinedwith feed prior to being fed to the burners of the gasifier. In oneembodiment, the burners of an entrained-flow gasifier comprise apressure atomizing burner. In another embodiment, the burner of anentrained-flow gasifier comprises a co-annular or multi-orifice burnercomprising blast atomization. Exemplary descriptions of a multi-orificeburner are provided by U.S. Pat. No. 5,273,212 and U.K. PatentApplication Publication No. GB2034456, the disclosures of which areincorporated herein by reference.

In general, in an exemplary embodiment, a multi-orifice burner comprisesa number of slits at the burner outlet and hollow wall members withinternal cooling fluid passages. The passages may or may not converge atthe burner outlet. Instead of comprising internal cooling fluidpassages, the burner may be provided with a suitable ceramic orrefractory lining applied onto or suspended adjacent to an outer surfaceof the burner (front) wall for resisting the heat load during operationof the burner. In certain embodiments, an exit of one or more passagesmay be retracted or protruded. The burner preferably has 4, 5, 6 or 7passages. A particular exemplary process to gasify liquid feed using anentrained flow gasifier equipped with a multi-orifice burner is providedby EPO Application Publication No. EP759886, the disclosure of which isincorporated herein by reference. In general, EP759886 describes aprocess for partial oxidation of a liquid carbonaceous feed where anoxidant and a liquid carbonaceous feed are supplied to a gasificationzone through a multi-orifice (co-annular) burner, such as thosedisclosed by U.S. Pat. No. 5,273,212 and GB2034456, comprising aconcentric arrangement of n passages or channels coaxial with thelongitudinal axis of the burner. As disclosed by EP759886, in aparticular embodiment, the oxidant, liquid carbonaceous feed, and amoderator gas are each supplied through separate channels of amulti-orifice (co-annular) burner having 6 passages. In one embodiment,either the oxidant or moderator gas is passed through the outermostpassage. In another embodiment where n is greater than or equal to 4,either the oxidant or moderator gas is also passed through the innermostpassage. In a non-limiting exemplary embodiment, the carbonaceous feedhas a viscosity in a range of about 1 to 1000 cP and passes through oneor more passages at a velocity in a range of about 2 to 30 m/s; theoxidant passes through one or more of the other passages at a velocityin a range of about 20 to 140 m/s; and the moderator gas passes throughone or more of the remaining passages at a velocity in a range of about5 to 140 m/s. In instances where viscous feed has a high content ofvolatile components, the gasification process described in U.S. Pat. No.7,569,156 can be used. The disclosure of U.S. Pat. No. 7,569,156 isincorporated herein by reference.

In one embodiment, if a multi-orifice burner is used with a gasifiersimilar to gasifier 700 of FIG. 7, the number of passages is preferably2. In another embodiment, if a multi-orifice burner is used with agasifier similar to gasifier 800 or 900, the number of passages ispreferably 2 to 6.

It is understood that one of ordinary skill in the art can select theappropriate gasifier(s) and operating conditions associated with theparticular gasifier(s) based on properties of bottom fraction 16 and/orbottom fraction 26 entering gasification system 17. Vice versa,properties of bottom fraction 16 and/or 26 can be adjusted to a certainextent to match the desired operating conditions of selectedgasifier(s). A combination of both is also possible where properties ofbottom fraction 16 and/or bottom fraction 26 as well as type andoperating conditions of selected gasifier(s) can be modified to achievedesired or optimal results, such as cost, efficiency, product quality,etc.

For example, if bottom fraction 16 and/or bottom fraction 26 aresufficiently fluid to be pumped, the slurry can be introduced intogasification system 17 alone, or as a suspension using a carrier fluid(not shown), such as air, nitrogen, carbon dioxide, carbon monoxide,syngas, hydrogen, steam, nitrogen-free gas, low-oxygen gas, oxygen-freegas, and/or a combination of these carrier fluids. In embodiments wherebottom fraction 16 and/or bottom fraction 26 are sufficiently fluid tobe pumped, gasification system 17 preferably comprises at least oneentrained-flow gasifier.

In another embodiment where the mixture is a solid at ambienttemperature, it can be dried and pulverized by an appropriate milling orcrushing apparatus, such as one or a series of ball mills, to produce aflowable solid. It can then be introduced into the gasifier using aconventional solid feed apparatus or with a carrier fluid. In a furtherembodiment where separation zone 14 may be remote from gasificationsystem 17, e.g., in another facility, bottom fraction 16 and/or bottomfraction 26 can be collected in a storage vessel and dried to pellets bystandard methods for easy handling and transporting. In embodimentswhere bottom fraction 16 and/or bottom fraction are introduced togasification system 17 as a solid, gasification system 17 can preferablycomprise any of the three types of gasifier: moving-bed, fluid-bed, orentrained flow. The size of the solid particles fed to the gasifier ispreferably formatted to suit the operating conditions of the selectedgasifier(s).

In one embodiment, one or more sorbents can also be introduced togasification system 17. The sorbents can capture one or morecontaminants from the syngas, such as sodium vapor in the gas phasewithin a gasifier.

In one embodiment, gas mixture 19 discharged from gasification system 17can be routed to WGS zone 20. In one embodiment, at least a portion ofgas mixture 19 can be further processed before it is introduced toreaction zone 20. Further processing can be part of gasification system17. For example, in certain embodiments, gasification system 17 canfurther comprise one or more particulate removal systems (not shown)and/or one or more cooling zones (not shown). In other embodiments,gasification system 17 can also include one or more hydrogen separators(not shown).

One or more particulate removal systems can be used to partially orcompletely remove any particulates from the syngas to provide theparticulates or particulate-containing fluid and a separated syngas. Theparticulate removal system can include a separation device for exampleconventional disengagers and/or cyclones. Particulate control devices(“PCD”) capable of providing an outlet particulate concentration belowthe detectable limit of about 0.1 parts per million by weight (ppmw) canalso be used. Examples of suitable PCDs can include, but are not limitedto, sintered metal filters, metal filter candles, and ceramic filtercandles (for example, iron alum inide filter material). Theparticulates, for example, fine ash, coarse ash, and combinationsthereof, can be recycled to the gasifier, purged from the system,utilized as the particulates, or any combination thereof.

If desired or necessary, the separated syngas can be cooled in one ormore syngas coolers in one or more cooling zones. For example, thesyngas can be cooled to about 540 degrees C. or less, such as about 300degrees C., using a suitable heat exchange system known to those skilledin the art. If a cooling zone is used, an exemplary non-limitingembodiment of a cooling zone is depicted in FIG. 10, with numeralreference 1000. Cooling system 1000 comprises gasification product inlet1002, cooling chamber 1004, cooled gasification product outlet 1006,cooling fluid inlet 1008, and heated fluid outlet 1010. Cooling chamber1004 comprises one or more conduits 1012 that wraps around coolingpassage 1014. In a preferred embodiment, cooling chamber 1004 comprisestwo conduits 1012. The inlet of one or more conduits 1012 is disposed ator near gasification product inlet 1006 and is arranged such that anoutlet of a gasifier is coupled to inlet 1006 so gasification product1020 exiting a gasifier and enters one or more conduits 1012. Coolingfluid inlet 1008 is coupled to cooling passage 1014 such that coolingfluid 1016 entering inlet 1008 flows through passage 1014 and exitscooling system 1000 as heated fluid 1018 through outlet 1010. It isunderstood that the location and/or position of various inlets andoutlets with respect to a top or bottom portion of cooling system 1000can be modified as appropriate.

During operation of the embodiment shown in FIG. 10, gasificationproduct 1020 enters cooling system 1000 through inlet 1002 and flowsthrough one or more conduits 1012 upward and exits cooling system 1000through outlet 1006 at a temperature that is lower than the temperaturewhen it entered cooling system 1000. Cooling fluid 1016 enters coolingsystem 1000 through inlet 1008 and flows through passage 1014 and exitscooling system 1000 as heated fluid 1018 through outlet 1010. Heatedfluid 1018 has a higher temperature than cooling fluid 1016. The flow ofgasification product 1020 around the flow of cooling fluid 1016 throughpassage 1014 allows for heat exchange between gasification product 1020and cooling fluid 1016, thereby cooling gasification product 1020 whileheating up cooling fluid 1016.

In certain embodiments, the separated and/or cooled syngas can betreated within a gas purification system to remove contaminants. The gaspurification system can include a system, a process, or a device toremove sulfur and/or sulfur-containing compounds from the syngas.Examples of a suitable catalytic gas purification system include, butare not limited to, systems using zinc titanate, zinc ferrite, tinoxide, zinc oxide, iron oxide, copper oxide, cerium oxide, or mixturesthereof. Examples of a suitable process-based gas purification systeminclude, but are not limited to, the SELEXOL® process, the RECTISOL®process, the CRYSTASULF® process, and the Sulfinol gas treatmentprocess.

In one embodiment, one or more amine solvents such asmethyl-diethanolamine (MDEA) can be used to remove acid gas from thesyngas. Physical solvents, for example SELEXOL® (dimethyl ethers ofpolyethylene glycol) or RECTISOL® (cold methanol), can also be used. Ifthe syngas contains carbonyl sulfide (COS), the carbonyl sulfide can beconverted by hydrolysis to hydrogen sulfide by reaction with water overa catalyst and then absorbed using the methods described above. If thesyngas contains mercury, the mercury can be removed using a bed ofsulfur-impregnated activated carbon.

One or more catalysts, such as a cobalt-molybdenum (“Co—Mo”) catalystcan be incorporated into the gas purification system to perform a sourshift conversion of the syngas. The Co—Mo catalyst can operate at atemperature of about 288° C. in the presence of H₂S, for example, about100 parts per million by weight (ppmw) H₂S. If a Co—Mo catalyst is usedto perform a sour shift, subsequent downstream removal of sulfur can beaccomplished using any of the above described sulfur removal methodsand/or techniques.

Gasification system 17 can also discharge ash or slag material (notshown), such as that described above. The slag material is optionallyrecycled back to gasification system 17 to increase the content of solidash-forming materials.

In WGS zone 20, carbon monoxide is converted to hydrogen in the presenceof steam through the water-gas shift reaction represented byCO+H₂O→CO₂+H₂. In one embodiment, steam generated by gasification system17 and/or a heat exchanger, if used, can provide at least a portion ofthe steam for the water-gas shift reaction. The water-gas shift processis well established as a means to increase the hydrogen content and/orreduce the carbon monoxide content of synthesis gases produced bygasification of carbonaceous material. In WGS zone 20, carbon monoxidereacts with steam at high temperature, and optionally in the presence ofone or more catalysts, to yield carbon dioxide and hydrogen. A mixtureof hydrogen, carbon dioxide, unreacted carbon monoxide and otherimpurities is discharged from WGS zone 20 as shifted synthesis gas. Atleast a portion of the hydrogen generated in WGS zone 20 is provided tohydrocatalytic treatment system 12 via hydrogen stream 21 for use inhydrocatalytic reactions.

In a preferred embodiment, WGS zone 20 can comprise one or more shiftreactors to adjust the hydrogen to carbon monoxide ratio (H₂:CO) of thesyngas by converting CO to CO₂. Within a shift reactor, a water-gasshift reaction reacts at least a portion of the carbon monoxide in thesyngas with water in the presence of a catalyst and a high temperatureto produce hydrogen and carbon dioxide. Examples of a suitable shiftreactor can include, but are not limited to, single stage adiabaticfixed bed reactors, multiple-stage adiabatic fixed bed reactors withinterstage cooling, steam generation or cold quench reactors, tubularfixed bed reactors with steam generation or cooling, fluidized bedreactors, or any combination thereof. A sorption enhanced water-gasshift (SEWGS) process, utilizing a pressure swing adsorption unit havingmultiple fixed bed reactors packed with shift catalyst and at hightemperature, e.g. a carbon dioxide adsorbent at about 480° C., can beused. Various shift catalysts can be employed.

In one embodiment, the shift reactor can include two reactors arrangedin series. A first reactor can be operated at high temperature (about340° C. to about 400° C.) to convert a majority of the CO present in thesyngas to CO, at a relatively high reaction rate using an iron-chromecatalyst. A second reactor can be operated at a relatively lowtemperature (about 145° C. to about 205° C.) to complete the conversionof CO to CO₂ using a mixture of copper oxide and zinc oxide.

In one embodiment, at least a portion of gas mixture 19 can be directedto a hydrogen separator (not shown) before it is routed to WGS zone 20.In another embodiment, which is not shown, at least a portion of gasmixture 19 can bypass WGS zone 20 and can be fed directly to thehydrogen separator. At least a portion of the hydrogen separated by thehydrogen separator can be fed to hydrocatalytic treatment system 12.

The hydrogen separator can include any system or device to selectivelyseparate hydrogen from syngas to provide a purified hydrogen stream anda waste gas stream. The hydrogen separator can provide a carbon dioxiderich fluid and a hydrogen rich fluid. The hydrogen separator can utilizepressure swing absorption, cryogenic distillation, and/or semi-permeablemembranes. Examples of suitable absorbents include, but are not limitedto, caustic soda, potassium carbonate or other inorganic bases, and/oralanolamines.

In one embodiment, the hydrogen generated in WGS zone 20 and/orseparately by a hydrogen separator can be routed to processing zone 22for use in hydrocatalytic reactions including further catalyticreduction reactions (e.g., hydrogenation reactions, hydrogenolysisreactions, hydrotreating reactions, and the like), further condensationreactions, isomerization reactions, oligomerization reactions, and anycombination thereof.

Accordingly, the hydrogen used in a hydrocatalytic reaction of system 12can include external hydrogen, recycled hydrogen, in situ generatedhydrogen, and any combination thereof. The term “in situ generatedhydrogen” as used herein refers to hydrogen that is produced within theoverall process; it is not limited to a particular reactor forproduction or use and is therefore synonymous with an in processgenerated hydrogen. As explained, at least one source of the hydrogenused in hydrocatalytic treatment system 12 comes from gasification ofbottom fraction 16 and/or bottom fraction 26, which is a product ofhydrocatalytic treatment system 12.

Descriptions of exemplary suitable hydrocatalytic reactions that cantake place in hydrocatalytic treatment system 12 are known to thoseskilled in the art and/or provided by U.S. Application Publication Nos.US2011/0154721, US2012/0152836, US2012/0156743, and US2013/0109896, andU.S. Application Nos. 61/665,641, filed on Jun. 28, 2012, and61/720,757, filed on Oct. 31, 2012, and 61/817,996, where eachdisclosure is incorporated herein by reference. Likewise, descriptionsof exemplary suitable further processing reactions that can take placein processing zone 22 are known to those skilled in the art and/orprovided by the materials that have been incorporated by reference intheir entirety. Accordingly, the details of hydrocatalytic reactions andfurther processing reactions need not be repeated.

Nevertheless, the descriptions below highlight some aspects of certainhydrocatalytic reactions, such as hydrothermal digestion and catalyticreduction reactions, and further processing reactions. It is understoodthat hydrocatalytic treatment system 12 can comprise any number,combination, and type of reactors to perform one or more hydrocatalyticreactions.

In certain embodiments where hydrocatalytic treatment system 12comprises hydrothermal digestion and one or more catalytic reductionreactions, the hydrothermal digestion and one or more catalyticreduction reactions take place in the same vessel, which can provide aneffective stabilization of soluble carbohydrates. The foregoing may beaccomplished by including a slurry catalyst capable of activatingmolecular hydrogen within a hydrothermal digestion unit containingcellulosic biomass solids. That is, the catalyst that is capable ofactivating molecular hydrogen may comprise a slurry catalyst. As usedherein, the term “slurry catalyst” refers to a catalyst comprisingfluidly mobile catalyst particles that can be at least partiallysuspended in a fluid phase via gas flow, liquid flow, mechanicalagitation, or any combination thereof. Formation of the reaction productmay reduce the amount of thermal decomposition that occurs duringhydrothermal digestion, thereby enabling high yield conversion ofcellulosic biomass solids into a desired reaction product to take placein a timely manner.

Once the soluble carbohydrates have been at least partially transformedinto a more stable reaction product during hydrothermal digestion,completion of the conversion of the soluble carbohydrates into thereaction product may take place in a separate catalytic reductionreactor unit that also employs the slurry catalyst or a differentcatalyst that is capable of activating molecular hydrogen. Thetransformation that takes place in the catalytic reduction reactor unitmay comprise a further reduction in the degree of oxidation of theinitial reaction product, an increased conversion of solublecarbohydrates into oxygenated intermediates, or both. As used herein,the term “oxygenated intermediates” refers to alcohols, polyols,ketones, aldehydes, and mixtures thereof that are produced from acatalytic reduction reaction of soluble carbohydrates.

Continuous, high temperature hydrothermal digestion may be accomplishedby configuring the biomass conversion systems such that fresh biomassmay be continuously or semi-continuously supplied to the hydrothermaldigestion unit, while it operates in a pressurized state. As usedherein, the term “continuous addition” and grammatical equivalentsthereof will refer to a process in which cellulosic biomass is added toa hydrothermal digestion unit in an uninterrupted manner without fullydepressurizing the hydrothermal digestion unit. As used herein, the term“semi-continuous addition” and grammatical equivalents thereof willrefer to a discontinuous, but as-needed, addition of biomass to ahydrothermal digestion unit without fully depressurizing thehydrothermal digestion unit.

In some embodiments described herein, a slurry catalyst may be used bothin the hydrothermal digestion unit and in the catalytic reductionreactor unit to mediate the catalytic reduction reaction of solublecarbohydrates into a reaction product. Retention of the slurry catalystin the hydrothermal digestion unit may also be aided by the low recycleratios that may be used in the biomass conversion systems describedherein. In any event, circulation of the slurry catalyst through thecellulosic biomass charge within the hydrothermal digestion unit canprovide good catalyst distribution within the biomass, thereby allowingsoluble carbohydrates to be effectively stabilized via a catalyticreduction reaction as soon as possible following their formation.

Since a slurry catalyst can be fluidly mobile, hydrogen sparge, solventrecycle, or any combination thereof may be used to distribute the slurrycatalyst throughout the cellulosic biomass charge in the hydrothermaldigestion unit. Good catalyst distribution in the cellulosic biomass mayimprove yields by intercepting soluble carbohydrates before they have anopportunity to degrade. Furthermore, use of a slurry catalyst may allowa fixed bed digestion unit to be more successfully used, sincemechanical stirring or like mechanical agitation is not needed to affectcatalyst distribution. This can allow higher biomass to solvent ratiosto be utilized per unit volume of the digestion unit than would bepossible in stirred tank or like digestion unit configurations.Furthermore, since stirring is not necessary, there is no express needto alter the size of the biomass solids prior to digestion taking place.

In one embodiment, poison-tolerant slurry catalyst is used. Use of apoison-tolerant catalyst may be particularly desirable, since catalystpoisons are not removed from the cellulosic biomass solids beforehydrothermal digestion and integrated catalytic reduction take place. Asused herein, a “poison-tolerant catalyst” is defined as a catalyst thatis capable of activating molecular hydrogen without needing to beregenerated or replaced due to low catalytic activity for at least about12 hours of continuous operation.

In some embodiments, suitable poison-tolerant catalysts may include, forexample, sulfided catalysts. In some or other embodiments, nitridedcatalysts may be used as poison-tolerant catalysts. Sulfided catalystssuitable for activating molecular hydrogen are described in commonlyowned U.S. application Ser. Nos. 13/495,785, filed on Jun. 13, 2012, and61/553,591, filed on Oct. 31, 2011, each of which is incorporated hereinby reference in its entirety. Sulfiding may take place by treating thecatalyst with hydrogen sulfide or an alternative sulfiding agent,optionally while the catalyst is disposed on a solid support. In moreparticular embodiments, the poison-tolerant catalyst may comprise asulfided cobalt-molybdate catalyst, such as a catalyst comprising about1-10 wt. % cobalt oxide and up to about 30 wt. % molybdenum trioxideprior to sulfidation. In other embodiments, catalysts containing Pt orPd may also be effective poison-tolerant catalysts for use in thetechniques described herein. When mediating in situ catalytic reductionreaction processes, sulfided catalysts may be particularly well suitedto form reaction products comprising a substantial fraction of glycols(e.g., C₂-C₆ glycols) without producing excessive amounts of thecorresponding monohydric alcohols. Although poison-tolerant catalysts,particularly sulfided catalysts, may be well suited for forming glycolsfrom soluble carbohydrates, it is to be recognized that other types ofcatalysts, which may not necessarily be poison-tolerant, may also beused to achieve a like result in alternative embodiments. As will berecognized by one having ordinary skill in the art, various reactionparameters (e.g., temperature, pressure, catalyst composition,introduction of other components, and the like) may be modified to favorthe formation of a desired reaction product. Given the benefit of thepresent disclosure, one having ordinary skill in the art will be able toalter various reaction parameters to change the product distributionobtained from a particular catalyst and set of reactants.

Catalysts that are not particularly poison-tolerant may also be used inconjunction with the techniques described herein. Such catalysts mayinclude, for example, Ru, Pt, Pd, or compounds thereof disposed on asolid support such as, for example, Ru on titanium dioxide or Ru oncarbon. Although such catalysts may not have particular poisontolerance, they may be regenerable, such as through exposure of thecatalyst to water at elevated temperatures, which may be in either asubcritical state or a supercritical state.

In some embodiments, slurry catalysts suitable for use in the methodsdescribed herein may be sulfided by dispersing a slurry catalyst in afluid phase and adding a sulfiding agent thereto. Suitable sulfidingagents may include, for example, organic sulfoxides (e.g., dimethylsulfoxide), hydrogen sulfide, salts of hydrogen sulfide (e.g., NaSH),and the like. In some embodiments, the slurry catalyst may beconcentrated in the fluid phase after sulfiding and then added to thehydrothermal digestion unit.

In some embodiments, the slurry catalyst may be operable to generatemolecular hydrogen. For example, in some embodiments, catalysts suitablefor aqueous phase reforming (i.e., APR catalysts) may be used. SuitableAPR catalysts may include, for example, catalysts comprising platinum,palladium, ruthenium, nickel, cobalt, or other Group VIII metals alloyedor modified with rhenium, molybdenum, tin, or other metals, or sulfided.However, in other embodiments, an external hydrogen feed may be used,optionally in combination with internally generated hydrogen.

In various embodiments, slurry catalysts used in embodiments describedherein may have a particulate size of about 250 microns or less. In someembodiments, the slurry catalyst may have a particulate size of about100 microns or less, or about 10 microns or less. In some embodiments,the minimum particulate size of the slurry catalyst may be about 1micron.

In general, digestion in the hydrothermal digestion unit may beconducted in a liquor phase. In some embodiments, the liquor phase maycomprise a digestion solvent that comprises water. In some embodiments,the liquor phase may further comprise an organic solvent. Although anyorganic solvent that is at least partially miscible with water may beused as a digestion solvent, particularly advantageous organic solventsare those that can be directly converted into fuel blends and othermaterials without being separated from hydrocatalytically treatedmixture 13. That is, particularly suitable organic solvents are thosethat may be co-processed along with hydrocatalytically treated mixture13 into fuel blends and other materials during further processingreactions. Suitable organic solvents in this regard may include, forexample, ethanol, ethylene glycol, propylene glycol, glycerol, and anycombination thereof. In some embodiments, the organic solvent maycomprise oxygenated intermediates produced from a catalytic reductionreaction of soluble carbohydrates. For example, in some embodiments, adigestion solvent may comprise oxygenated intermediates produced by ahydrogenolysis reaction or other catalytic reduction reaction of solublecarbohydrates. In some embodiments, the oxygenated intermediates mayinclude those produced from an in situ catalytic reduction reactionand/or from the catalytic reduction reactor unit.

In some embodiments employing hydrothermal digestion, the digestionsolvent may further comprise a small amount of a monohydric alcohol. Thepresence of at least some monohydric alcohols in the fluid phasedigestion medium may desirably enhance the hydrothermal digestion and/orthe catalytic reduction reactions being conducted therein. For example,inclusion of about 1% to about 5% by weight monohydric alcohols in thefluid phase digestion medium may desirably maintain catalyst activitydue to a surface cleaning effect. Monohydric alcohols present in thedigestion solvent may arise from any source. In some embodiments, themonohydric alcohols may be formed via the in situ catalytic reductionreaction process being conducted therein. In some or other embodiments,the monohydric alcohols may be formed during further chemicaltransformations of the initially formed hydrocatalytically treatedmixture 13. In still other embodiments, the monohydric alcohols may besourced from an external feed that is in flow communication with thecellulosic biomass solids.

In some embodiments, the digestion solvent may comprise between about 1%water and about 99% water. Although higher percentages of water may bemore favorable from an environmental standpoint, higher quantities oforganic solvent may more effectively promote hydrothermal digestion dueto the organic solvent's greater propensity to solubilize carbohydratesand promote catalytic reduction of the soluble carbohydrates. In someembodiments, the digestion solvent may comprise about 90% or less waterby weight. In other embodiments, the digestion solvent may compriseabout 80% or less water by weight, or about 70% or less water by weight,or about 60% or less water by weight, or about 50% or less water byweight, or about 40% or less water by weight, or about 30% or less waterby weight, or about 20% or less water by weight, or about 10% or lesswater by weight, or about 5% or less water by weight.

In some embodiments, the digestion solvent may comprise an organicsolvent comprising oxygenated intermediates resulting from a catalyticreduction reaction of soluble carbohydrates. The catalytic reductionreaction may take place in the hydrothermal digestion unit and/or in thecatalytic reduction reactor unit. In some embodiments, the organicsolvent may comprise at least one alcohol, ketone, or polyol. Inalternative embodiments, the digestion solvent may be at least partiallysupplied from an external source. For example, in some embodiments,bio-ethanol may be used to supplement the organic solvent. Otherwater-miscible organic solvents may be used as well. In someembodiments, the digestion solvent may be separated, stored, orselectively injected into the hydrothermal digestion unit so as tomaintain a desired concentration of soluble carbohydrates or to providetemperature regulation in the hydrothermal digestion unit.

In various embodiments, digestion may take place over a period of timeat elevated temperatures and pressures. In some embodiments, digestionmay take place at a temperature ranging between about 100 to about 240degrees C. for a period of time. In some embodiments, the period of timemay range of about 0.25 to 24 hours. In some embodiments, the digestionto produce soluble carbohydrates may occur at a pressure ranging betweenabout 1 bar (absolute) and about 100 bar. In general, the higher thetemperature, the shorter the amount of time needed for hydrothermaldigestion steps to take place. As an example, hydrothermal digestion maytake place for about 1 hour to about 10 hours at a temperature of about180 to about 270 degrees C., most typically from about 190 to 250degrees C.

In various embodiments, suitable biomass digestion techniques mayinclude, for example, acid digestion, alkaline digestion, enzymaticdigestion, and digestion using hot-compressed water. In someembodiments, the methods may further comprise withdrawing at least aportion of the reaction product from the biomass conversion system(e.g., from the outlet of the catalytic reduction reactor unit or fromthe fluid circulation loop). In some embodiments, the methods mayfurther comprise converting the reaction product into a biofuel, asdescribed in further detail hereinafter. In some embodiments, themethods may further comprise separating solids (e.g., slurry catalyst,biomass fines, and the like) from the reaction product after itswithdrawal from the biomass conversion system, as described above.

In some embodiments, the methods may further comprise recirculating atleast a portion of the liquor phase from the catalytic reduction reactorunit to the hydrothermal digestion unit. As set forth above, the biomassconversion systems described herein are particularly advantageous inbeing capable of rapidly at least partially transforming solublecarbohydrates into a reaction product comprising oxygenatedintermediates by performing an in situ catalytic reduction reaction inthe hydrothermal digestion unit. As also noted above, the liquor phasecontaining the reaction product may be recirculated from the catalyticreduction reactor unit to the hydrothermal digestion unit, where theliquor phase may, for example, help regulate temperature therein, serveas a digestion solvent, and the like. Recirculation from the catalyticreduction reactor unit to the hydrothermal digestion unit may take placeat various recycle ratios. As used herein, the term “recycle ratio”refers to the amount of liquor phase that is recirculated to thehydrothermal digestion unit (e.g., within the fluid circulation loop)relative to the amount of liquor phase that is withdrawn from thebiomass conversion system (e.g., by a reaction product takeoff line).

In some embodiments, the catalytic reduction reactions carried out maybe hydrogenolysis reactions. In some embodiments, the catalyticreduction reaction may take place at a temperature ranging between about110° C. and about 300° C., or between about 170° C. and about 300° C.,or between about 180° C. and about 290° C., or between about 150° C. andabout 250° C. In some embodiments, the catalytic reduction reaction maytake place at a pH ranging between about 7 and about 13, or betweenabout 10 and about 12. In other embodiments, the catalytic reductionreaction may take place under acidic conditions, such as at a pH ofabout 5 to about 7. Acids, bases, and buffers may be introduced asnecessary to achieve a desired pH level. In some embodiments, thecatalytic reduction reaction may be conducted under a hydrogen partialpressure ranging between about 1 bar (absolute) and about 150 bar, orbetween about 15 bar and about 140 bar, or between about 30 bar andabout 130 bar, or between about 50 bar and about 110 bar.

In some embodiments, catalysts capable of activating molecular hydrogenand conducting a catalytic reduction reaction may comprise a metal suchas, for example, Cr, Mo, W, Re, Mn, Cu, Cd, Fe, Co, Ni, Pt, Pd, Rh, Ru,Ir, Os, and alloys or any combination thereof, either alone or withpromoters such as Au, Ag, Cr, Zn, Mn, Sn, Bi, B, O, and alloys or anycombination thereof. In some embodiments, the catalysts and promotersmay allow for hydrogenation and hydrogenolysis reactions to occur at thesame time or in succession of one another. In some embodiments, suchcatalysts may also comprise a carbonaceous pyropolymer catalystcontaining transition metals (e.g., Cr, Mo, W, Re, Mn, Cu, and Cd) orGroup VIII metals (e.g., Fe, Co, Ni, Pt, Pd, Rh, Ru, Ir, and Os). Insome embodiments, the foregoing catalysts may be combined with analkaline earth metal oxide or adhered to a catalytically active support.In some or other embodiments, the catalyst capable of activatingmolecular hydrogen may be deposited on a catalyst support that is notitself catalytically active.

In some embodiments, slurry catalysts suitable for use in the methodsdescribed herein may be sulfided by dispersing a slurry catalyst in afluid phase and adding a sulfiding agent thereto. Suitable sulfidingagents may include, for example, organic sulfoxides (e.g., dimethylsulfoxide), hydrogen sulfide, salts of hydrogen sulfide (e.g., NaSH),amino acids derived from proteins present in biomass feedstock 11 andthe like. In some embodiments, the slurry catalyst may be concentratedin the fluid phase after sulfiding, and the concentrated slurry may thenbe distributed in the cellulosic biomass solids using fluid flow.Illustrative techniques for catalyst sulfiding that may be used inconjunction with the methods described herein are described in U.S.application Ser. No. 12/407,479 (U.S. Application Publication No.20100236988), filed on Mar. 19, 2009 and incorporated herein byreference in its entirety.

In some embodiments, as mentioned above, hydrocatalytically treatedmixture 13, preferably as overhead fraction 15, may be further processedinto a biofuel. Further processing of hydrocatalytically treated mixture13 and/or overhead fraction 15 into a biofuel or other material maycomprise any combination and sequence of further hydrogenolysisreactions and/or hydrogenation reactions, condensation reactions,isomerization reactions, oligomerization reactions, hydrotreatingreactions, alkylation reactions, dehydration reactions, desulfurizationreactions, and the like. The subsequent further processing reactions maybe catalytic or non-catalytic. In some embodiments, an initial operationof downstream further processing may comprise a condensation reaction,often conducted in the presence of a condensation catalyst, in whichhydrocatalytically treated mixture 13, overhead fraction 15, and/or aproduct derived therefrom is condensed with another molecule to form ahigher molecular weight compound. As used herein, the term “condensationreaction” will refer to a chemical transformation in which two or moremolecules are coupled with one another to form a carbon-carbon bond in ahigher molecular weight compound, usually accompanied by the loss of asmall molecule such as water or an alcohol. An illustrative condensationreaction is the Aldol condensation reaction, which will be familiar toone having ordinary skill in the art. Additional disclosure regardingcondensation reactions and catalysts suitable for promoting condensationreactions is provided hereinbelow.

In some embodiments, methods described herein may further compriseperforming a condensation reaction on hydrocatalytically treated mixture13, overhead fraction 15, and/or a product derived therefrom. In variousembodiments, the condensation reaction may take place at a temperatureranging between about 5° C. and about 500° C. The condensation reactionmay take place in a condensed phase (e.g., a liquor phase) or in a vaporphase. For condensation reactions taking place in a vapor phase, thetemperature may range between about 75° C. and about 500° C., or betweenabout 125° C. and about 450° C. For condensation reactions taking placein a condensed phase, the temperature may range between about 5° C. andabout 475° C., or between about 15° C. and about 300° C., or betweenabout 20° C. and about 250° C.

In various embodiments, the higher molecular weight compound produced bythe condensation reaction may comprise ≧C₄ hydrocarbons. In some orother embodiments, the higher molecular weight compound produced by thecondensation reaction may comprise ≧C₆ hydrocarbons. In someembodiments, the higher molecular weight compound produced by thecondensation reaction may comprise C₄-C₃₀ hydrocarbons. In someembodiments, the higher molecular weight compound produced by thecondensation reaction may comprise C₆-C₃₀ hydrocarbons. In still otherembodiments, the higher molecular weight compound produced by thecondensation reaction may comprise C₄-C₂₄ hydrocarbons, or C₆-C₂₄hydrocarbons, or C₄-C₁₈ hydrocarbons, or C₆-C₁₈ hydrocarbons, or C₄-C₁₂hydrocarbons, or C₆-C₁₂ hydrocarbons. As used herein, the term“hydrocarbons” refers to compounds containing both carbon and hydrogenwithout reference to other elements that may be present. Thus,heteroatom-substituted compounds are also described herein by the term“hydrocarbons.”

The particular composition of the higher molecular weight compoundproduced by the condensation reaction may vary depending on thecatalyst(s) and temperatures used for both the catalytic reductionreaction and the condensation reaction, as well as other parameters suchas pressure. For example, in some embodiments, the product of thecondensation reaction may comprise ≧C₄ alcohols and/or ketones that areproduced concurrently with or in lieu of ≧C₄ hydrocarbons. In someembodiments, the ≧C₄ hydrocarbons produced by the condensation reactionmay contain various olefins in addition to alkanes of various sizes,typically branched alkanes. In still other embodiments, the ≧C₄hydrocarbons produced by the condensation reaction may also comprisecyclic hydrocarbons and/or aromatic compounds. In some embodiments, thehigher molecular weight compound produced by the condensation reactionmay be further subjected to a catalytic reduction reaction to transforma carbonyl functionality therein to an alcohol and/or a hydrocarbon andto convert olefins into alkanes.

Exemplary compounds that may be produced by a condensation reactioninclude, for example, ≧C₄ alkanes, ≧C₄ alkenes, ≧C₅ cycloalkanes, ≧C₅cycloalkenes, aryls, fused aryls, ≧C₄ alcohols, ≧C₄ ketones, andmixtures thereof. The ≧C₄ alkanes and ≧C₄ alkenes may range from 4 toabout 30 carbon atoms (i.e. C₄-C₃₀ alkanes and C₄-C₃₀ alkenes) and maybe branched or straight chain alkanes or alkenes. The ≧C₄ alkanes and≧C₄ alkenes may also include fractions of C₇-C₁₄, C₁₂-C₂₄ alkanes andalkenes, respectively, with the C₇-C₁₄ fraction directed to jet fuelblends, and the C₁₂-C₂₄ fraction directed to diesel fuel blends andother industrial applications. Examples of various ≧C₄ alkanes and ≧C₄alkenes that may be produced by the condensation reaction include,without limitation, butane, butene, pentane, pentene, 2-methylbutane,hexane, hexene, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane,2,3-dimethylbutane, heptane, heptene, octane, octene,2,2,4,-trimethylpentane, 2,3-dimethylhexane, 2,3,4-trimethylpentane,2,3-dimethylpentane, nonane, nonene, decane, decene, undecane, undecene,dodecane, dodecene, tridecane, tridecene, tetradecane, tetradecene,pentadecane, pentadecene, hexadecane, hexadecene, heptyldecane,heptyldecene, octyldecane, octyldecene, nonyldecane, nonyldecene,eicosane, eicosene, uneicosane, uneicosene, doeicosane, doeicosene,trieicosane, trieicosene, tetraeicosane, tetraeicosene, and isomersthereof.

The ≧C₅ cycloalkanes and ≧C₅ cycloalkenes may have from 5 to about 30carbon atoms and may be unsubstituted, mono-substituted ormulti-substituted. In the case of mono-substituted and multi-substitutedcompounds, the substituted group may include a branched ≧C₃ alkyl, astraight chain ≧C₁ alkyl, a branched ≧C₃ alkylene, a straight chain ≧C₁alkylene, a straight chain ≧C₂ alkylene, an aryl group, or a combinationthereof. In some embodiments, at least one of the substituted groups mayinclude a branched C₃-C₁₂ alkyl, a straight chain C₁-C₁₂ alkyl, abranched C₃-C₁₂ alkylene, a straight chain C₁-C₁₂ alkylene, a straightchain C₂-C₁₂ alkylene, an aryl group, or a combination thereof. In yetother embodiments, at least one of the substituted groups may include abranched C₃-C₄ alkyl, a straight chain C₁-C₄ alkyl, a branched C₃-C₄alkylene, a straight chain C₁-C₄ alkylene, a straight chain C₂-C₄alkylene, an aryl group, or any combination thereof. Examples of ≧C₅cycloalkanes and ≧C₅ cycloalkenes that may be produced by thecondensation reaction include, without limitation, cyclopentane,cyclopentene, cyclohexane, cyclohexene, methylcyclopentane,methylcyclopentene, ethylcyclopentane, ethylcyclopentene,ethylcyclohexane, ethylcyclohexene, and isomers thereof.

The moderate fractions of the condensation reaction, such as C₇-C₁₄, maybe separated for jet fuel, while heavier fractions, such as C₁₂-C₂₄, maybe separated for diesel use. The heaviest fractions may be used aslubricants or cracked to produce additional gasoline and/or dieselfractions. The ≧C₄ compounds may also find use as industrial chemicals,whether as an intermediate or an end product. For example, the arylcompounds toluene, xylene, ethylbenzene, para-xylene, meta-xylene, andortho-xylene may find use as chemical intermediates for the productionof plastics and other products. Meanwhile, C₉ aromatic compounds andfused aryl compounds, such as naphthalene, anthracene,tetrahydronaphthalene, and decahydronaphthalene, may find use assolvents or additives in industrial processes.

In some embodiments, a single catalyst may mediate the transformation ofhydrocatalytically treated mixture 13 and/or overhead fraction 15 into aform suitable for undergoing a condensation reaction as well asmediating the condensation reaction itself. In other embodiments, afirst catalyst may be used to mediate the transformation ofhydrocatalytically treated mixture 13 and/or overhead fraction 15 into aform suitable for undergoing a condensation reaction, and a secondcatalyst may be used to mediate the condensation reaction. Unlessotherwise specified, it is to be understood that reference herein to acondensation reaction and condensation catalyst refers to either type ofcondensation process. Further disclosure of suitable condensationcatalysts now follows.

In some embodiments, a single catalyst may be used to form a highermolecular weight compound via a condensation reaction. Without beingbound by any theory or mechanism, it is believed that such catalysts maymediate an initial dehydrogenation of hydrocatalytically treated mixture13 and/or overhead fraction 15, followed by a condensation reaction ofthe dehydrogenated alcoholic component. Zeolite catalysts are one typeof catalyst suitable for directly converting alcohols to condensationproducts in such a manner. A particularly suitable zeolite catalyst inthis regard may be ZSM-5, although other zeolite catalysts may also besuitable.

In some embodiments, two catalysts may be used to form a highermolecular weight compound via a condensation reaction. Without beingbound by any theory or mechanism, it is believed that the first catalystmay mediate an initial dehydrogenation of hydrocatalytically treatedmixture 13 and/or overhead fraction 15, and the second catalyst maymediate a condensation reaction of the dehydrogenated hydrocatalyticallytreated mixture 13 and/or overhead fraction 15. Like the single-catalystembodiments discussed previously above, in some embodiments, zeolitecatalysts may be used as either the first catalyst or the secondcatalyst. Again, a particularly suitable zeolite catalyst in this regardmay be ZSM-5, although other zeolite catalysts may also be suitable.

Various catalytic processes may be used to form higher molecular weightcompounds by a condensation reaction. In some embodiments, the catalystused for mediating a condensation reaction may comprise a basic site, orboth an acidic site and a basic site. Catalysts comprising both anacidic site and a basic site will be referred to herein asmulti-functional catalysts. In some or other embodiments, a catalystused for mediating a condensation reaction may comprise one or moremetal atoms. Any of the condensation catalysts may also optionally bedisposed on a solid support, if desired.

In some embodiments, the condensation catalyst may comprise a basiccatalyst comprising Li, Na, K, Cs, B, Rb, Mg, Ca, Sr, Si, Ba, Al, Zn,Ce, La, Y, Sc, Y, Zr, Ti, hydrotalcite, zinc-aluminate, phosphate,base-treated aluminosilicate zeolite, a basic resin, basic nitride,alloys or any combination thereof. In some embodiments, the basiccatalyst may also comprise an oxide of Ti, Zr, V, Nb, Ta, Mo, Cr, W, Mn,Re, Al, Ga, In, Co, Ni, Si, Cu, Zn, Sn, Cd, Mg, P, Fe, or anycombination thereof. In some embodiments, the basic catalyst maycomprise a mixed-oxide basic catalyst. Suitable mixed-oxide basiccatalysts may comprise, for example, Si—Mg—O, Mg—Ti—O, Y—Mg—O, Y—Zr—O,Ti—Zr—O, Ce—Zr—O, Ce—Mg—O, Ca—Zr—O, La—Zr—O, B—Zr—O, La—Ti—O, B—Ti—O,and any combination thereof. In some embodiments, the condensationcatalyst may further include a metal or alloys comprising metals suchas, for example, Cu, Ag, Au, Pt, Ni, Fe, Co, Ru, Zn, Cd, Ga, In, Rh, Pd,Ir, Re, Mn, Cr, Mo, W, Sn, Bi, Pb, Os, alloys and combinations thereof.Use of metals in the condensation catalyst may be desirable when adehydrogenation reaction is to be carried out in concert with thecondensation reaction. Basic resins may include resins that exhibitbasic functionality. The basic catalyst may be self-supporting oradhered to a support containing a material such as, for example, carbon,silica, alumina, zirconia, titania, vanadia, ceria, nitride, boronnitride, a heteropolyacid, alloys and mixtures thereof.

In some embodiments, the condensation catalyst may comprise ahydrotalcite material derived from a combination of MgO and Al₂O₃. Insome embodiments, the condensation catalyst may comprise a zincaluminate spinel formed from a combination of ZnO and Al₂O₃. In stillother embodiments, the condensation catalyst may comprise a combinationof ZnO, Al₂O₃, and CuO. Each of these materials may also contain anadditional metal or alloy, including those more generally referencedabove for basic condensation catalysts. In more particular embodiments,the additional metal or alloy may comprise a Group 10 metal such Pd, Pt,or any combination thereof.

In some embodiments, the condensation catalyst may comprise a basiccatalyst comprising a metal oxide containing, for example, Cu, Ni, Zn,V, Zr, or any mixture thereof. In some or other embodiments, thecondensation catalyst may comprise a zinc aluminate containing, forexample, Pt, Pd, Cu, Ni, or any mixture thereof.

In some embodiments, the condensation catalyst may comprise amulti-functional catalyst having both an acidic functionality and abasic functionality. Such condensation catalysts may comprise ahydrotalcite, a zinc-aluminate, a phosphate, Li, Na, K, Cs, B, Rb, Mg,Si, Ca, Sr, Ba, Al, Ce, La, Sc, Y, Zr, Ti, Zn, Cr, or any combinationthereof. In further embodiments, the multi-functional catalyst may alsoinclude one or more oxides from the group of Ti, Zr, V, Nb, Ta, Mo, Cr,W, Mn, Re, Al, Ga, In, Fe, Co, Ir, Ni, Si, Cu, Zn, Sn, Cd, P, and anycombination thereof. In some embodiments, the multi-functional catalystmay include a metal such as, for example, Cu, Ag, Au, Pt, Ni, Fe, Co,Ru, Zn, Cd, Ga, In, Rh, Pd, Ir, Re, Mn, Cr, Mo, W, Sn, Os, alloys orcombinations thereof. The basic catalyst may be self-supporting oradhered to a support containing a material such as, for example, carbon,silica, alumina, zirconia, titania, vanadia, ceria, nitride, boronnitride, a heteropolyacid, alloys and mixtures thereof.

In some embodiments, the condensation catalyst may comprise a metaloxide containing Pd, Pt, Cu or Ni. In still other embodiments, thecondensation catalyst may comprise an aluminate or a zirconium metaloxide containing Mg and Cu, Pt, Pd or Ni. In still other embodiments, amulti-functional catalyst may comprise a hydroxyapatite (HAP) combinedwith one or more of the above metals.

In some embodiments, the condensation catalyst may also include azeolite and other microporous supports that contain Group IA compounds,such as Li, Na, K, Cs and Rb. Preferably, the Group IA material may bepresent in an amount less than that required to neutralize the acidicnature of the support. A metal function may also be provided by theaddition of group VIIIB metals, or Cu, Ga, In, Zn or Sn. In someembodiments, the condensation catalyst may be derived from thecombination of MgO and Al₂O₃ to form a hydrotalcite material. Anothercondensation catalyst may comprise a combination of MgO and ZrO₂, or acombination of ZnO and Al₂O₃. Each of these materials may also containan additional metal function provided by copper or a Group VIIIB metal,such as Ni, Pd, Pt, or combinations of the foregoing.

The condensation reaction mediated by the condensation catalyst may becarried out in any reactor of suitable design, includingcontinuous-flow, batch, semi-batch or multi-system reactors, withoutlimitation as to design, size, geometry, flow rates, and the like. Thereactor system may also use a fluidized catalytic bed system, a swingbed system, fixed bed system, a moving bed system, or a combination ofthe above. In some embodiments, bi-phasic (e.g., liquid-liquid) andtri-phasic (e.g., liquid-liquid-solid) reactors may be used to carry outthe condensation reaction.

In some embodiments, an acid catalyst may be used to optionallydehydrate at least a portion of the reaction product. Suitable acidcatalysts for use in the dehydration reaction may include, but are notlimited to, mineral acids (e.g., HCl, H₂SO₄), solid acids (e.g.,zeolites, ion-exchange resins) and acid salts (e.g., LaCl₃). Additionalacid catalysts may include, without limitation, zeolites, carbides,nitrides, zirconia, alumina, silica, aluminosilicates, phosphates,titanium oxides, zinc oxides, vanadium oxides, lanthanum oxides, yttriumoxides, scandium oxides, magnesium oxides, cerium oxides, barium oxides,calcium oxides, hydroxides, heteropolyacids, inorganic acids, acidmodified resins, base modified resins, and any combination thereof. Insome embodiments, the dehydration catalyst may also include a modifier.Suitable modifiers may include, for example, La, Y, Sc, P, B, Bi, Li,Na, K, Rb, Cs, Mg, Ca, Sr, Ba, and any combination thereof. Themodifiers may be useful, inter alia, to carry out a concertedhydrogenation/dehydrogenation reaction with the dehydration reaction. Insome embodiments, the dehydration catalyst may also include a metal.Suitable metals may include, for example, Cu, Ag, Au, Pt, Ni, Fe, Co,Ru, Zn, Cd, Ga, In, Rh, Pd, Ir, Re, Mn, Cr, Mo, W, Sn, Os, alloys, andany combination thereof. The dehydration catalyst may be selfsupporting, supported on an inert support or resin, or it may bedissolved in a fluid.

Various operations may optionally be performed on hydrocatalyticallytreated mixture 13 and/or overhead fraction 15 prior to conducting acondensation reaction. In addition, various operations may optionally beperformed on a fluid phase containing hydrocatalytically treated mixture13 and/or overhead fraction 15, thereby further transforminghydrocatalytically treated mixture 13 and/or overhead fraction 15 orplacing it in a form more suitable for taking part in a condensationreaction. These optional operations are now described in more detailbelow.

As described above, one or more liquid phases may be present whendigesting cellulosic biomass solids. Particularly when cellulosicbiomass solids are fed continuously or semi-continuously to thehydrothermal digestion unit, digestion of the cellulosic biomass solidsmay produce multiple liquid phases in the hydrothermal digestion unit.The liquid phases may be immiscible with one another, or they may be atleast partially miscible with one another. In some embodiments, the oneor more liquid phases contained in hydrocatalytically treated mixture 13and/or overhead fraction 15 may comprise a phenolics liquid phasecomprising lignin or a product formed therefrom, an aqueous phasecomprising an alcoholic component, a light organics phase, or anycombination thereof.

In some embodiments, heating of biomass feedstock 11 and the fluid phasedigestion medium to form soluble carbohydrates and a phenolics liquidphase may take place while biomass feedstock 11 is in a pressurizedstate. As used herein, the term “pressurized state” refers to a pressurethat is greater than atmospheric pressure (1 bar). Heating a fluid phasedigestion medium in a pressurized state may allow the normal boilingpoint of the digestion solvent to be exceeded, thereby allowing the rateof hydrothermal digestion to be increased relative to lower temperaturedigestion processes. In some embodiments, heating biomass feedstock 11and the fluid phase digestion medium may take place at a pressure of atleast about 30 bar. In some embodiments, heating biomass feedstock 11and the fluid phase digestion medium may take place at a pressure of atleast about 60 bar, or at a pressure of at least about 90 bar. In someembodiments, heating biomass feedstock 11 and the fluid phase digestionmedium may take place at a pressure ranging between about 30 bar andabout 430 bar. In some embodiments, heating biomass feedstock 11 and thefluid phase digestion medium may take place at a pressure rangingbetween about 50 bar and about 330 bar, or at a pressure ranging betweenabout 70 bar and about 130 bar, or at a pressure ranging between about30 bar and about 130 bar.

To facilitate a better understanding of the present invention, thefollowing examples of preferred embodiments are given. In no way shouldthe following examples be read to limit, or to define, the scope of theinvention.

EXAMPLES

To facilitate a better understanding of the present invention, thefollowing examples of preferred embodiments are given. In no way shouldthe following examples be read to limit, or to define, the scope of theinvention.

Example 1

A 100-ml Parr reactor was charged with 60.18 grams of deionized watersolvent, and 0.754 grams of nickel-oxide promoted cobalt molybdatecatalyst (DC-2534, containing 1-10% cobalt oxide and molybdenum trioxide(up to 30 wt %) on alumina, and less than 2% nickel), obtained fromCriterion Catalyst & Technologies L.P. The catalyst was sulfided by themethod described in Example 5 of U.S. Application Publication No.2010/0236988. The reactor was charged with about 5.05 grams of southernpine mini-chips (39% moisture, having a nominal size of about 3 mm×5mm×5 mm in dimension), and about 0.195 grams of potassium carbonatebuffer, before pressuring with 54 bar of hydrogen under magneticstirring. The stirred reactor was heated to 190° C. for 1 hour.Subsequently, the reactor was heated to 250° C. for 5 hours, which wasthe end of a cycle. A sample of about 1-2 grams of mixed product wasremoved via a 0.5 micron sintered metal dip tube at the end of thecycle, while the reactor was still at reaction temperature and stirred.At the end of a cycle, the reactor was cooled, depressurized, and openedfor additional wood to be added. Wood addition for cycles 2 through 5entailed addition of 4.91, 5.09, 5.84, and 5.59 grams of wood. For cycle6, 2.5 grams of glycerol were added to assess kinetics. For cycle 7, 5.9grams of nominal 39% moisture ground pine chips were added. For cycle 8,6.5 grams of pine chips were added. Following the addition of material(wood or glycerol) at the beginning of each cycle, the reactor wasrepressurized with hydrogen, and again reheated to initiate anothercycle. After eight cycles of adding wood or glycerol, the 0.5 micronsintered metal dip tube plugged, and it was not possible to sample themixed reaction phases. The mixture from the reactant was cooled down anda bottom fraction was separated by liquid-liquid separation. The bottomfraction exhibited a viscosity of greater than about 10,000 cP, measuredvia timing and flow on an inclined plane while reheating to about 110degrees C.

The bottom fraction was analyzed by gas chromatography (“DB5-ox method”)via dissolving the sample in excess acetone solvent using a 60-m×0.32 mmID DB-5 column of 1 μm thickness, with 50:1 split ratio, 2 ml/min heliumflow, and column oven at 40° C. for 8 minutes, followed by ramp to 285°C. at 10° C./min, and a hold time of 53.5 minutes. The injectortemperature was set at 250° C., and the detector temperature was set at300° C. Analysis revealed the presence of components with a boilingpoint greater than that of n-butanol, and the bottom fraction includedmethoxypropyl phenol and tetrahydrofurfural alcohol. The total weightpercent of species detected in the bottom fraction was less than 100%,indicating the presence of higher molecular weight oligomers which couldnot elute from the heated GC injector.

Example 1 shows separation of a bottom fraction containing alignin-derived phase from a top fraction liquid phase, where the bottomfraction contains phenolics and other heavy oligomers. This bottomfraction can be gasified to form hydrogen according to embodiments ofthe invention.

Example 2

Example 1 was repeated with 60.06 grams of 25% ethanol in water assolvent, and 0.749 grams of sulfided cobalt molybdate catalyst. Thereactor was pressurized to 52 bar with hydrogen, and heated to 190° C.for 1 hour, then to 250° C. for 3 hours, and subsequently to 270° C. for2 hours. After 8 cycles of adding 6 grams of wood for each cycle asdescribed above in Example 1, formation of a viscous phase on reactorinternals was observed. The viscous phase exhibited a viscosity greaterthan 1000 cP at room temperature. This phase was separated usingliquid-liquid separation to generate a bottom fraction. Analysis of thisheavy bottoms fraction again revealed the presence of compounds with aboiling point that is higher than that of n-butanol, includingtetrahydrofurfural alcohol and methoxypropyl phenol and propyl phenol.The total weight percent of species detected in the bottom fraction wasless than 100%, indicating the presence of higher molecular weightoligomers which could not elute from the heated GC injector. Example 2also shows the formation of a heavy phase which can be separated from amain reaction mixture by gravity settling, and which can be gasified toform hydrogen according to embodiments of the invention.

Example 3

Example 1 was repeated with 50% ethanol in water as solvent. A heavyviscous phase coating internals and the bottom of the reactor wasobserved after 10 cycles of adding wood chips as described above inExample 1, with viscosity greater than 10,000 cP. Wood additionscomprised 6.05, 6.06, 6.06, 6.06, 6.01, 6.00, 6.01, 6.02, 6.06, and 6.06for completion of ten cycles. After the 10 cycles, the reactor wassubjected to 5 hours of treatment under 52 bar of H₂ at 290° C., uponwhich the viscosity of the lower layer was reduced to less than about500 cP. The high temperature hydrogen treatment led to increasedformation of methoxy and alkyl phenols, such that the observed weightpercent of compounds in the GC was more than 3-fold higher than for thesimilar phase formed in Example 2. The treated phase can be distilled toremove the components of lower volatility that can elute from a GCinjector. The remaining bottom fraction containing heavy components,which comprise the unseen weight percent in the GC analysis, can berouted to a gasifier to form hydrogen according to embodiments of theinvention.

Example 4

A 100-ml Parr reactor was charged with a solvent mixture comprising 29.3grams of 1,2-propylene glycol, 3.3 grams of ethylene glycol, and 32.5grams of deionized water. 0.75 grams of nickel-oxide promoted cobaltmolybdate catalyst were added (DC-2534, containing 1-10% cobalt oxideand molybdenum trioxide (up to 30 wt %) on alumina, and less than 2%nickel), obtained from Criterion Catalyst & Technologies L.P., andsulfided by the method described in US2010/0236988 Example 5.

The reactor was charged with 6.1 grams of southern pine mini-chips (39%moisture), of nominal size 3×5×5 mm in dimension, before pressuring with53 bar of hydrogen. The stirred reactor was heated to 190° C. for 1hour, and subsequently heated to 250° C. for 5 hours to complete a cycleas described above in Example 1.

At the end of each cycle, 5.4 grams of product were withdrawn via apipette. 6.0 grams of wood were charged to initiate a second reactioncycle using the protocol described in Example 1, along with 0.05 to 0.15grams of buffer as needed to maintain pH between 5 and 6. Reactorproduct after each cycle was analyzed by gas chromatography using a60-m×0.32 mm ID DB-5 column of 1 μm thickness, with 50:1 split ratio, 2ml/min helium flow, and column oven at 40° C. for 8 minutes, followed byramp to 285° C. at 10° C./min, and a hold time of 53.5 minutes. Theinjector temperature was set at 250° C., and the detector temperaturewas set at 300° C. The reaction sequence was continued through 45cycles. At the end of cycle 45, 19.1262 grams of aqueous phase weredecanted from the viscous heavy components phase. The remaining viscousheavy components phase can be gasified to form hydrogen according toembodiments of the invention.

A distillation of the aqueous layer was conducted at ambient pressureunder N2 blanket, using a 50-ml micro flask with short-path distillationhead. The distillation was continued until 58% of the initial stillcontents were collected as overhead distillate. A first distillation cutwas taken as bottoms temperature increased from 120 to 168 degrees C. Asecond distillation cut was taken at bottoms temperatures between 169and 186 degrees C. The atmospheric distillation was terminated at 196.9degrees C. bottoms temperature, and gave a fraction comprising diols andacids.

The distillation of this fraction was resumed under vacuum at a nominalpressure of 10 Torr. A maximum temperature of 279 degrees C. wasobtained, and 32% of the heavy ends from vacuum distillation wererecovered as overhead distillate. The resulting bottom fraction fromvacuum distillation was dissolved in dichloromethane and analyzed by GCMS. Many components were too heavy to analyze. Overall structuresresembled asphaltenes, with some phenolic groups present.

The distillation bottoms flask was unwrapped and tipped sideways todemonstrate flow of heavy residue at a bottoms temperature of about 268degrees C., at an estimated viscosity in excess of 1000 cP. About 82% ofthe final residue could be poured out of the hot flask. Upon cooling,the residue would not flow and required removal by spatula for sampling.

This example shows thermal distillation of intermediate production fromdigestion-reaction of wood biomass using a catalyst capable ofactivating molecular hydrogen, under a hydrogen atmosphere. Mono- anddi-oxygenates which can be coupled via condensation-oligomerationreactions could be separated by distillation at atmospheric pressure andunder vacuum, leaving a heavy tar-like residue. The heavy residue couldbe kept molten to flow out of distillation kettle when heated above 250degrees C. This bottom fraction from vacuum distillation containingheavy residues can be gasified to form hydrogen according to embodimentsof the present invention. Alternatively, the temperature of theatmospheric distillation can be increased to produce a bottom fractionthat may be routed to a gasifier according to embodiments of the presentinvention.

Example 5

Example 4 was repeated using 4-methyl-2-pentanol (methyl isobutylcarbinol or “MIBC”) as the digestion medium, and with use of largerscale batches were run conducted in a 450 mL Parr reactor. The reactorwas initially charged with 220.06 g of MIBC, 25.08 g deionized water,0.855 g of potassium carbonate buffer, and 8.1065 g of sulfidedcobalt-molybdate catalyst as described in Example 1. For each reactioncycle, 27 g of softwood pine mini-chips were added, and an equivalentamount of liquid sample was removed at the end of each cycle. For liquidsample removal after each cycle, a portion of the lower aqueous layerwas removed from as liquid above the settled catalyst layer, if present,followed by removal of a sufficient amount of the upper layer ifrequired to maintain the liquid inventory in the reactor at a 60% level.After 17 cycles, a sample of the upper layer was distilled atatmospheric pressure under nitrogen, followed by vacuum distillation at10 Torr. Distillate cut number 2 was collected under nitrogen atatmospheric pressure with a kettle bottoms temperature of about 110 to140 degrees C. and an overheads temperature of about 90 degrees C. Cutnumber 2 contains a mixture of oxygenated and alkane intermediates. Witha kettle temperature of about 258 to 302 degrees C., a vacuumdistillation cut containing an estimated 30% of the reactor product wasobtained as distillate cut number 6. In addition to alcohols (includingglycols and other diols), significant quantities of phenolic compoundswere obtained in cut number 6. For example, methoxy propyl phenol wasfound to be present in quantities greater than 4%. Tetrahydrofurfuralalcohol was also found as a significant reaction product. No observableviscous layer or tar was formed under the experimental conditions ofExample 5. A final vacuum distillation cut representing the end point ofdistillation (final 1% of feed) is produced and reported in Table 1below.

TABLE 1 Final vacuum distillation cut at 348 degrees C. bottomtemperature Name area % acetone (diluent) N/A 1-butanol (int standard)N/A 4-methyl-2-Pentanol N/A tetrahydro Furanmethanol 3.27% phenol 6.93%methoxy phenol 8.61% methyl phenol 12.39%  unknown 3.89% dimethy phenol7.37% methyl methoxy phenol 6.27% ethyl phenol 6.15% methyl ethyl phenol5.51% unknown 2.58% ethyl methoxy phenol 5.24% unknown 3.76% propylphenol 6.09% unknown 0.91% benzene diol 5.24% propyl methoxy phenol6.30% unknown 1.15% unknown 2.50% unknown 5.84%

The distillation flask bottoms after distillation with a finaltemperature of about 345 degrees C. continued to boil and bubble, butformed a solid char with resemblance to coal, upon cooling to roomtemperature. This example shows digestion and reaction intermediates.Distillation allows removal of monooxygenates and diols, with somephenols. Some heavy tar components with separation points in excess of350 degrees C. remain in the bottoms, and for a char phase upon cooling.At least one of distillation cut number 6, the final vacuum distillationcut, and the heavy tar components remaining in the bottoms can begasified to form hydrogen according to embodiments of the invention.

Example 6

Example 5 was repeated with 34 cycles of wood addition. Distillation wasconducted at atmospheric pressure under N₂ to remove 85% of the reactorcontents as overhead product, analyzed as a mixture of monooxygenatesand some diols. The remaining 15% kettle bottoms formed a non-flowableviscous tar at room temperature, for which dissolution in acetonesolvent required reheating. The remaining 15% kettle bottoms can begasified to form hydrogen according to embodiments of the invention.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as the presently preferred embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims.

The invention claimed is:
 1. A method comprising: (a) providing abiomass feedstock comprising cellulose and water; (b) contacting thebiomass feedstock with hydrogen in the presence of a catalyst capable ofactivating molecular hydrogen in a hydrocatalytic treatment at atemperature in a range of about 180 to 290 degrees C. to form ahydrocatalytically treated mixture comprising a plurality of hydrocarbonand oxygenated hydrocarbon molecules; (c) separating thehydrocatalytically treated mixture into at least a first overheadfraction comprising at least one of the hydrocarbon and oxygenatedhydrocarbon molecules and a first bottom stream comprising at least onecompound having a separation point having a temperature in a range ofabout 100 to 600 degrees C. at a pressure of about atmospheric pressure,wherein the first bottom fraction comprises at least one of phenol,o-cresol, p-cresol, anisole, 4-methylanisole, catechol, guaiacol,4-methylguaiacol, 1,3-dimethoxybenzene, syringol, vanillin,methoxyphenol, methyl phenol, dimethyl phenol, ethyl phenol, methylethyl phenol, methoxypropylphenol, benzene diol, and propyl phenol; (d)partially oxidizing the first bottom fraction to produce a gas mixturecomprising carbon monoxide and hydrogen; (e) providing the gas mixtureto a water gas shift reaction zone external to where the biomassfeedstock is contacted with hydrogen to generate hydrogen and carbondioxide; and (f) providing the hydrogen from step (e) for use in step(b).
 2. The method of claim 1 wherein the first bottom fractioncomprises at least one compound having a separation point having atemperature in a range of about 100 to 500 degrees C. at a pressure in arange of about 1 to 100 Torr.
 3. The method of claim 1 wherein the firstoverhead fraction is subject to a further processing reaction to producea product stream comprising a higher molecular weight compoundcomprising ≧C₄ hydrocarbons.
 4. The method of claim 3 furthercomprising: separating the product stream comprising a higher molecularweight compound comprising ≧C₄ hydrocarbons into a second overheadfraction and a second bottom fraction, wherein the second bottomfraction comprises at least one compound having a separation pointhaving a temperature in a range of about 100 to 500 degrees C. at apressure in a range of about 75 to 5250 Torr and wherein the secondbottom fraction comprises C₁₄ or greater hydrocarbons; partiallyoxidizing the second bottom fraction to produce a gas mixture comprisingcarbon monoxide and hydrogen; subjecting the gas mixture generated frompartial oxidation of the second bottom fraction to a water gas shiftreaction to generate hydrogen and carbon dioxide; and providing thehydrogen from the second bottom fraction to step (b).
 5. The method ofclaim 4 wherein the second bottom fraction comprises at least onecompound having a separation point having a temperature in a range ofabout 150 to 400 degrees C. at a pressure in a range of about 75 to 5250Torr.
 6. The method of claim 1 wherein the partially oxidizing step ofthe first bottom fraction comprises using a gasifier.
 7. The method ofclaim 6 wherein the gasifier is selected from the group consisting of amoving-bed gasifier, a fluid-bed gasifier, an entrained-flow gasifier,and any combination thereof.
 8. The method of claim 6 further comprisingrouting the first bottom fraction to the gasifier, wherein said firstbottom fraction is a solid, liquid, or combination thereof.
 9. Themethod of claim 8 wherein the gasifier comprises an entrained-flowgasifier and said first bottom fraction is routed as a liquid.
 10. Themethod of claim 4 wherein the partially oxidizing step of the secondbottom fraction comprises using a gasifier.
 11. The method of claim 10wherein the same gasifier is used for the partially oxidizing step ofthe first bottom fraction and the partially oxidizing step of the secondbottom fraction.
 12. The method of claim 1 wherein the first bottomfraction subject to partial oxidation has a viscosity of about 1 to10,000 centipoise (cP) at a temperature of about 75 degrees C.
 13. Themethod of claim 1 wherein the first bottom fraction subject to partialoxidation has a viscosity of about 320 centistokes or less at atemperature at which the first bottom fraction is produced.
 14. Themethod of claim 1 wherein the first bottom fraction subject to partialoxidation comprises at least one component selected from lignin, alignin-derived compound, unextracted cellulose, unextractedhemicellulose, and a caramelan.
 15. The method of claim 1 wherein thehydrocatalytic treatment occurs in liquid phase.
 16. The method of claim1 wherein the hydrocatalytic treatment occurs in an aqueous phasesolvent.
 17. The method of claim 1 wherein the hydrocatalytic treatmentoccurs in an organic phase solvent.
 18. The method of claim 1 whereinthe first bottom fraction comprises at least one compound having aseparation point having a temperature in a range of about 200 to 450degrees C. at a pressure of about 3 to 20 Torr.